forgotten that Dinornis, like other ratites, except Apteryx, has a single head to the quadrate. In the characters of the pelvis Dinornis is near to Apteryx and the Casuariidae and remote from Rhea (as well as from Struthio). The large aftershaft allies it to the Casuariidæ. NATHUSIUS has commented upon the practical identity in egg-shell structure which Rhea shows to Dinornis, a likeness which impressed him so greatly that he proposed to place them in the same genus. A considerable number of the special relations between Apteryx and the Dinornithidæ, upon which FÜRBRINGER Writes, such as failing pneumaticity, absence of clavicle, mutual distance between coracoids, and even the form of the sternum, may largely depend upon the loss of flight, which is more complete in these birds than in the ostrich, for example. In no less than three footnotes FÜRBRINGER Comments upon the supposed absence of uncinate processes to the ribs of the Dinornithida; but this difference from other ratites does not exist, as T. J. PARKER has definitely asserted their presence. It is significant that in his tables of differential characters FÜRBRINGER refers little to those of the fore limb girdle (including sternum) as distinguishing Dinornithidæ from Rhea. Α detailed account of the pros and cons will be found in the systematic part of FÜRBRINGER's work, and as regards the skull in PARKER'S paper already referred to.

The Struthiones have been often held to be more primitive than any of the existing groups of birds.

There are really, however, not a large series of characters in which they may be fairly said to be more primitive than some other groups, and most of these are shared by some others.

The form of the palate and the single-headed quadrate appears to be a low character; but the former is shared with the tinamous, the latter with some other groups. The incompleteness of the fusion of the cranial bones may be looked at in the same way; but the penguin is on the same level as the Struthiones. The absence of any fusion distally between the bones of the pelvis in Apteryx and Dinornis is

dinosaurian; but the tinamous are like Apteryx in this. The complete procoracoid of Struthio seems to be an archaic character, as do the two free centralia in the foot of Apteryx. As to negative characters, the most important of those that are possibly, but not certainly, to be regarded as primitive appears to be the usual absence of the oil gland.

The long rectum of Struthio is probably an ancient character; but whether the absence of a bird-like syrinx in all ratites except Rhea is a similar feature seems to be doubtful. The large size of the blood corpuscles in the ratites is noteworthy in this connection.

The following table gives the principal characters of the existing genera. From it may be inferred the somewhat less modified condition of Apteryx and the very isolated position of Struthio among the members of the group :

GROUP SAURURÆ

SAURORNITHES

As there is but a single genus, and in all probability but a single species,' in this group, it is useless to attempt any formal definitions of family or other characters. I shall merely give the more important facts in its structure, as I have with the foregoing groups. As to external characters, the Archeopteryx has an anisodactyle foot, like that of the Passeres. The feet and the digits of the manus have been stated to have been covered with scales. That scales may have been present, at least on the foot, is very probable, but there is not the faintest evidence of their having been there. Of feathers the remiges and rectrices are plain, while of the general body feathering there is not so much evidence. With the exception of a circle of feathers upon the neck, suggestive of those of the condor, and similar rings of feathers upon the ankle, it is thought by some that the Archeopteryx was naked. Most of the restorations, however, admit a general feathering. The chief criticism to be offered is the extreme perfection of the remains of such feathers as are visible in the slab of stone in which the dead bird was originally imbedded. This being the case, the apparent absence of feathers over the general body surface gains more weight. That they may have been present and of the nature of down feathers is believed by reason of certain faint indications of something to round the contours of the body; the group of contour feathers upon the leg are plainly visible even in photographs of the Berlin example. This example is much better than the specimen in London, which is the only other skeleton in existence. The rectrices are quite obvious, a pair to each of the separate vertebræ of the tail. There appear to have been not fewer than thirty

It has been argued that specific and even generic differences exist between the London and Berlin examples.

M M

of these; FÜRBRINGER places the number between that figure and forty. Most of the restorations allow thirtytwo or thirty-four. This number is important; it is in excess of that generally found in living birds, although the tail itself is not composed of actually more vertebræ. Among recent birds it is perhaps a significant fact that the penguins alone have this number. Of remiges seventeen appears to have been the number, six or seven primaries and ten secondaries. No existing bird has so few primaries, the nearest approach being nearly all the Anomalogonata (and some other birds too), which have ten. There is some difference of opinion as to how these remiges were attached to the arm and hand. DAMES, in his elaborate monograph upon Archeopteryx, puts forward the view that they were attached to the metacarpal and down to the claw of digit II. MENZBIER limits the attachment of the primaries to the basal phalanx of the third, not second digit. FÜRBRINGER thinks that the greater number of the primaries were attached to metacarpal III. and the third finger, only a few being inserted upon the phalanges of digit II., where the latter is overlapped by the last-mentioned digit. HURST has adopted the revolutionary view that there are missing, and probably cartilaginous, digits IV. and V., to which the primaries were attached. As to the presumed additional fingers, if they were really present, where did they articulate? The entire available space appears to be taken up with the digits which are already known. In its primaries Archæopteryx is the very reverse of the penguin, which it appears to resemble in its rectrices. The exceptional number to be found in that bird is not in the least explained by the conditions observable in Archæopteryx. A beak seems to have been absent in Archæopteryx, owing to the fact that the teeth extend to the end of the jaws. The vertebral column of this bird has some fifty vertebræ, of which ten or eleven are reckoned cervical; the smallness of the number, which probably belongs to this category, is only approached among the parrots and the Pico-Passeres and some of their nearest allics, where, however, thirteen is the