If in this discussion of some of the highest relations of physiology, we have not wandered too far from our subject proper which we have thereby sought to illustrate indirectly, we will revert to the thread of its discourse for a few concluding remarks.

The final question now is, what is the legitimate interpretation to be put upon the reproductive phenomena of the Aphides we have described? My answer to this has been anticipated in the foregoing remarks. I regard the whole as constituting only a rather anomalous form of gemmiparity. As already shown, the viviparous Aphides are sexless; they are not females, for they have no proper female organs, no ovaries and oviducts. These viviparous individuals, therefore, are simply gemmiparous, and the budding is here internal instead of external as in the Polyps and Acalephs; it, moreover, takes on some of the morphological peculiarities of oviparity, but all these dissimilar conditions are economical and extrinsic, and do not touch the intrinsic nature of the processes concerned therein.

Viewed in this way, the different broods of Aphides cannot be said to constitute as many true generations any more than the different branches of a tree can be said to constitute as many trees; on the other hand, the whole suite from the first to the last constitute but a single true generation. I would insist upon this point as illustrative of the distinction to be drawn between sexual and gemmiparous reproduction. Morphologically, they have, it is true, many points of close resemblance; but there is a grand physiological difference, the true perception of which is deeply connected with our highest appreciation of individual animal life. A true generation must be regarded as resulting only from the conjugation of two opposite sexes-from a sexual process in which the potential representations of two individuals are united for the elimination of one germ. This germ-power may be extended by gemmation or by fission, but it can be formed only by the act of generation, and its play of extension and prolongation by budding, or by division, must always be within a certain cycle, and this cycle is recommenced by the new act of the conjugation again of the sexes.

In this way, the dignity of the ovum as the primordium of all true individuality is maintained; and the axiom of Harvey, omne vivum er ovo, stands as golden in physiology. The buds may put on the dress and the forms of the ovum, but these resemblances are extrinsic and in fact only an inheritance from their great predecessor.

In this view as well as in several others herein discussed, I am pleased to say that I have the support of so learned a physiologist as Dr. Carpenter. See his Review "On the development and Metamorphoses of Zoophytes" in the Brit. and Foreign Med. Chir. Rev., 1848, i. p. 183; and "On Reproduction and Repair" in Ibid. 1849, ii, p. 419.

These phenomena thus interpretated, furnish us an excellent key to many others which have long been regarded as anomalous, in the history of development.

I refer here to the so-called hibernating eggs (Wintereier) which are found in many Invertebrates. These I have not seen, but they have been carefully described by several very trustworthy observers. These so-called eggs consist of oval masses or cells invested with a capsule, but in which no germinative vesicle and dot have ever been seen. Structurally, therefore, they do not resemble eggs, and it is from their form and ulterior development only that they have received this name. Moreover, they sustain none of the usual relations of eggs to the sexual organs, and, as far as I am aware, no one has witnessed their development in the ovaries. These bodies have been observed in Hydatina* and Notommatat among the Infusoria; in Lacinulariat among the Rotatoria; and in Daphnias among the Crustacea. In all these instances they hatch without the aid of the male, the existence of which sex was once doubted from its infrequent appearance. Now I regard these hibernating eggs as merely egg-like buds exactly corresponding to the germs of the viviparous Aphides. In other words, there are in the animals I have just mentioned, certain individuals which reproduce by buds which are developed under rather anomalous conditions; and I will add in conclusion, that I suspect that this gemmiparous mode of reproduction will be found to be far from uncommon among most of the Invertebrata, when our researches into the history of their development shall have been more widely extended.

* Ehrenberg, “Die Infusionsthierchen," p. 413. + Dalrymple, Philos. Trans. 1849. p. 340.

*Healey, Quarterly Jour. Micr. Sc. 1852. i, p. 13.

$ Moller, Entomostraca, p. 84. Tab. xr, fig. 9-11, Tab. xi. fig. 5. Also, Roudohr, Beiträge zur Naturgesch, einiger deutschen Monokulus-Arten, 1805. p. 28; Strauss, Mém. sur les Daphnia, in the Mém. du Mus. d'Hist. Nat., v, p. 413. Pl. XXIX; Jurine, Histoire des Monocles, 1820. p. 120. Pl. x1, fig. 1-4. Jurine calls these egregated eggs La maladie de la selle."

There is, moreover, reason to believe that these anomalous reproductive conditions occur in nearly all the Entomostraca:-see Siebold and Stannius's Comparative Anat. My transl. vol. i, my note under § 292, note 4.

$ Notice may here be given of some curious observations, which Filipi (Ann. Nat. Hist, ix, 1852. p. 461) has furnished on the development of the Pteromalidæ. A Pteromalus lives in the ova of Rhumchites betuleti; in each of these ova, there is seen, soon after its deposit, a minute infusorial animal, with a tail by which it moves briskly about among the vitelline cells. It soon ceases to move, however, and in its interior appears a vesicle which increases an I changes into a larva which is that of Pteromalus; this larva becomes a pupa, and, after eight or ten days, changes to the perfect insect which escapes from the ovum.

If these observations are verified, we have here a case exactly like that of the Aphides, excepting that like the Distoma, the intermediate budding form is very low, and takes on none of the zoological peculiarities of the parent. But these statements need corroboration, for they do not agree with the history of other species of Pteromalus whose development is well known. See also, the wonderful gemmiparous phenomena related by Siebold of Gyrodactylus; Siebold and Kolliker's Zeitsch. f. wiss. Zool, i, 1849. p. 347.

P. S.-I regret that I should not have seen until now, when this paper is concluded, the important writings of Leydig on the subject under discussion. In his article "Einige Bemerkungen über die Entwickelung der Blattläuse" in Siebold and Kolliker's Zeitsch. f. wiss. Zool. ii, 1850. p. 62, he speaks of his former observations in the Isis, 1848, iii, p. 184. These I have not seen, neither also a work to which he refers, of J. Victor Carus, (Zu näheren Kenntniss des Generationswecshels, Leipzig, 1849.) Leydig in his criticism of Carus's views, expresses the opinion that the development of the viviparous Aphides is, histologically, like that of the Articulata in general. According to him, also, the germbodies undergo processes corresponding to those of impregnated eggs. These statements of Leydig, who is an excellent observer, have induced me recently to repeat my observations; but this afforded the same results as before, viz.: that the germ-bodies out of which are developed the viviparous Aphides, have no true histological identity with eggs.

ART. VIII.—Mineralogical Contributions; by JAMES D. DANA. 1. Brooke and Miller's Mineralogy.

THE reviewer of this work in volume xv, page 41, mentions but briefly its importance in a crystallographic point of view. It is in this department eminently an original work, the result of special researches on the crystallization of very many of the species, with the measurement and calculation of their angles. It must therefore be long a standard work. Mr. Brooke has been indefatigable in his crystallographic studies, and early became prominent in English mineralogy by his Introduction to Crystallography, published in 1823; Professor Miller is no less distinguished for the precision and accuracy of his labors in physical science. The number of angles of each species given is very large, and there is a mathematical exactness and system in the selection of those which are mentioned, according with the methods of calculation. The circles filled in with dots, accompanying the descriptions of the species, afford much assistance in apprehending the positions of planes. The eye when looking down upon a crystal from above, an axis being in the line of vision, sees the planes arranged symmetrically, around the axis: and on describing a circle about the axis as its centre, if dots corresponding each in position to the normal of a plane, be placed in the circle, an ideal view, or rather the mathematical essence of the crystal, will be presented. Such are the circles referred to. The great deficiency in the work is the want of proper figures to aid in applying these ideal representations so as to give an actual shape to the mind correspond

ing with the habits of the species. Moreover, another method of tabulating the planes may accomplish the same result more simply, we think, and one in which the planes shall be indicated by their true expressions, instead of arbitrary letters. The method alluded to, has already been presented in this Journal, in the writer's paper on Sphene and Euclase. It contrasts with the method in Brooke and Miller's work mainly as Mercator's projection of a sphere contrasts with the spherical projection.

The method of calculation adopted, is based for the most part on spherical trigonometry. It is less general in its formulas and less elegant, we think, than the system from analytical geometry, but sometimes affords more concise equations. The hexagonal system is rather at variance with itself in the method used. The planes are referred to three axes, the three lines that connect the centres of opposite faces in a rhombohedron. The plan is not objectionable as regards the rhombohedral section of the hexagonal system. But in the hexagonal section of this system, in which the symmetrical parts are by sixes instead of threes, the planes of a simple dihexagonal pyramid require two sets of symbols in place of one: that is, where two identical planes occur about the same angle of a hexagonal prism, as in beryl, these must have different mathematical expressions. This leads the mathematician to no error; but tends to perplex a simple subject for the student.

But these are minor points, and leave the work still, the most accurate, thorough, and original work on the crystallization of minerals that has been published.

2. Von Kobell's "Mineral-Namen."*

Prof. von Kobell, introduces the subject of his work by many judicious and pithy remarks on the multitude of synonyms in mineralogy, and the varieties of structure, derivation and formation, exhibited among the names of species. He next classifies the names according to their derivation, and explains their etymology. He presents, First, a catalogue of those names that are of mythological origin. Second, leaving the gods and mythology, he passes to those derived from the names of cultivators of the science, collectors of specimens, patrons, statesmen, and what not, among whom, about two hundred and thirty are hereby commemorated, not immortalized, for amid the fatality to which mineral species are subject and the custom of change in authors, very many of the names are already in the rubbish heaps of the science. Third, comes a list of the names derived from localities; fourth, those alluding to the structure of the species; fifth, those based

* Die Mineral-Namen und die mineralogische Nomenklatur, von Franz von Kobell, 162 pp. 8vo; München, 1853. Briefly mentioned in this Journal, page 304, vol. xvi.

on color; sixth, on other physical characters; seventh, on chemical composition and reactions; eighth, names derived from other peculiarities, uses, arbitrary or fanciful allusions; ninth, those of unknown or doubtful origin. After speaking of the importance of a universal nomenclature for different countries, Prof. von Kobell lays down several rules for nomenclature in mineralogy, requiring that names derived from names of persons or localities should be written according to their original orthography, and not altered for each different language; that the Greek language should be used, rarely the Latin, for the derivation of other names; that the earliest name of a species should be retained, only when correctly formed in accordance with these principles: and he gives a list of some names that have been more or less recently proposed as substitutes for earlier objectionable names, the general adoption of which he observes would tend to make mineralogical language the same the world over. The greater part of these names are already accepted in the science.

It may be doubted whether, by carrying out with full strictness, his laws, we may not in some cases, create more confusion than we avoid, especially in the case of species well known in the arts. For example in substituting, as is proposed, Liparite (Glocker) for Fluor or Fluor spar (Fluss or Flusspath, of the Germans), we are giving a new word to science, without special significance in itself, and making confusion between the terms. of the arts and science. As mineralogy is but a semi-science,

and its nomenclature but a convenient means of designation without a proper scientific basis, we should hesitate before adopting new names in cases like the above. Print it Liparite and still the mineral will be called fluor.

Blende or Zineblende is another case of this kind. We cannot consider Glocker's Sphalerite a needed substitute for the old Hematite is an unfortunate substitute for specular iron, as it is restricting to narrow limits an old name of wider signification; and in this country, it is the most common designation of the species limonite. It is however coming into common use in Europe and Great Britain. Arsenite for arsenous acid, and Chromite for chromic iron, are objectionable names, as the termination is a chemical one for a section of salts. Galenite is not an improvement on Galena, as the word is as appropriate without

the "ite."

Horn silver (Hornsilber of the German), although two words and obnoxious to the criticism of not being Greek, is significant and contains fewer syllables and letters than Kerargyrite,-or Cerargyrite as the word should be written with us. For Silver glance, early called Argyrose by Beudant, Haidinger's name Argentite is adopted by von Kobell. Clay is dignified with the name of Argillite. Azurite of Beudant (Blue Malachite, Kup