absence of a biceps slip to the patagium. Its leg muscle formula too is that of a heron.

Besides these facts

which incline to both the stork and the heron side, and which, perhaps, are the most important of such facts--it may be mentioned that Scopus shows a stork-like character in the partial division of the pectoralis primus,

a fact which was first pointed out by FORBES incidentally, in his report upon the petrels collected during the voyage of the Challenger.' The patagial muscles and tendons are not specially distinctive of the affinities of the bird. In my dissection of Scopus I could not find the expansor secundariorum; but as this muscle is found in most of the Herodiones its absence is not in any way significant, though it should doubtless be verified. The anconaus has a tendinous slip to the humerus. The deep plantar tendons appear to vary somewhat; in two specimens dissected by myself I met with the two conditions illustrated in the two

FIG. 196.-DEEP
PLANTAR TENDONS
BEDDARD).
OF Scopus (AFTER

.

figures annexed. In the one the flexor hallucis was united to the flexor communis by two distinct vincula, one before the trifurcation of the latter tendon, the other attached to the tendon supplying digit II. In a specimen of Ciconia nigra dissected by FORBES there was an identical arrangement. In the other Scopus (see fig. 195) only the last of the two vincula was present, i.e. that passing to tendon of digit II.

For the skeleton of Scopus see MILNE-EDWARDS's account.'

The skull is on the whole more stork-like than heron-like, but it does not show any of the extreme modifications of the stork type. The bony interorbital septum, as in the storks, is not largely fenestrate. The inner lamina of the palatines does not reach the posterior boundary of those bones. In front, at about the middle of the interpalatine vacuity, the palatines are produced into a short lateral process; this is well marked in many storks, but also in Cancroma, to the skull of which heron that of Scopus shows another point of likeness; in both (AFTER these birds a deepish groove runs from the end of the nostril to the end of the bill. This groove is also found, though it is not so conspicuous, in Ardea and Butorides, and (among storks only) in Platalea; it is suggestive of a recently closed, more elongated nostril, like that of the cranes. The procoracoid is more rudimentary than in storks, but the coracoids overlap at insertion.

OF

Family Ciconiidæ. I include in this family not only the true storks but also the wood ibises (Tantalus). GARROD2

1 Histoire Naturelle, &c., de Madagascar, 'Oiseaux,' p. 514.

2 F. E. BEDDARD, Notes on the Convoluted Trachea of a Curassow (Nothocrax urumutum), and on the Syrinx in certain Storks,' P. Z. S. 1886, p. 321.

contrasted Ibis and Platalea on the one hand with Ciconia and Tantalus on the other, on account of the following differences:

To which I add the form of the syrinx. These collectively appear to me to justify this separation. The true

FIG. 198.-SYRINX OF Dissura FIG. 199. SYRINX OF Abdimia sphenoepiscopus (AFTER BEDDARD). rhyncha (AFTER BEDDARD).

storks, including Tantalus, are well characterised by the peculiar structure of the trachea and syrinx, there being, as already mentioned, an approach in these birds to the purely tracheal syrinx of the tracheophone Passeres. In the common black stork, C. nigra, the syrinx has the form illustrated in the figure (fig. 197). Its principal features are the absence of intrinsic muscles, the modification of the last tracheal rings, the existence of a rudimentary vocal process (see p. 69), and the closed character of the bronchial rings, which are rings, not semi-rings, the membrana tympani

formis being absent. In Xenorhynchus senegalensis, however (fig. 200), there is some approach to the more typical tracheo-bronchial syrinx, which is further developed in Abdimia sphenorhyncha and Dissura episcopus;1 the syringes of these two storks are illustrated herewith (figs. 199,

FIG. 200.-SYRINX OF Xenorhynchus senegalensis (AFTER BEDDARD).

198). In the former as well as in the latter the intrinsic muscles are still absent, and there is a considerable modification of the last tracheal rings; but in both there is a partial deficiency of cartilage where the membrana tympaniformis is developed in other birds. In Xenorhynchus this

is but slight; in Abdimia and Dissura episcopus it is well shown. But the latter bird has the complete bronchidesmus which marks the ciconiine as contrasted with the ardeine. syrinx (cf. figs. 194 and 198). In Mycteria americana the bronchial rings are complete, but thinner internally, which is a hint of the otherwise absent membrana tympaniformis. The genus Tantalus is unique among the Ciconiidæ in having a convoluted trachea. This, however, is now known to occur only in the male of T. ibis; in both sexes of T. loculator the trachea is unconvoluted. In the former bird the tube makes several intrathoracic loops, as shown in the figure (fig. 201). The syrinx is essentially stork-like.

In most storks the muscle formula of the leg is AXY +; 2 the only exceptions to this yet known are Xenorhynchus senegalensis, Dissura episcopus, and Abdimia sphenorhyncha, where the ambiens is absent, and Leptoptilus crumeniferus and argala, where there is no femorocaudal. The tendency to an ardeine structure in the syrinx of these birds has already been remarked upon, and may possibly be correlated with the absence of the ambiens. Storks have no biceps slip, but a typical expansor secundariorum. The humeral head of the anconæus is generally present. The patagial tendons are usually of a somewhat complicated form.

The tensor patagii brevis is constituted upon a similar plan in all storks, though there are naturally some little differences in detail.

In Leptoptilus, according to WELDON, there is but one tendon which, widening out just before its insertion on to the fore arm, gives off a recurrent slip to the tendon of the longus.

In Ciconia nigra, according to FÜRBRINGER, the tendons

On the Trachea of Tantalus,' &c., P. Z. S. 1878, p. 625; On the Form of the Trachea in certain Species of Storks and Spoonbills,' ibid. 1875, p. 297.

2 A. H. GARROD, 'Note on an Anatomical Peculiarity in certain Storks,' ibid. 1877, p. 711. In a specimen of Xenorhynchus australis a few fibres corresponding to the accessory femorocaudal were found.

3 Loc. cit. (on p. 419).