SKULL OF THE ^GITHOaNATHOUS BIRDS. 291 



well conjoined, all but the short crura. Whilst at the mid line, in front, there is a slight 

 carination, towards the side there is some evidence of such a process of absorption as 

 would cut off a lateral falciform septo-maxillary. Seen from above (fig. 7, v, i. al) these 

 sides are thick, and form the walls of the scooped bone ; they are grafted upon the 

 inturned alinasal cartilage. This part of the nasal vestibule is forked, as in the Wren 

 (Trans. Linn. Soc. ser. 2, Zool. vol. i. pi. 21. fig. 6), the larger process being above and 

 outside, and the lesser below and more mesiad. 



This lower and inner process sends inwards to the septum a crescentic tongue of 

 floor-cartilage {n.f) ; it has a sinuous front and a convex hinder edge. Then the 

 main part of the floor, on each side of the septum, is membranous ; the septum 

 itself (figs. 6 & 7, s. n) is not alate. At its extremity the prsenasal region has a 

 small rod of cartilage (fig. 6, p.n) ; and the recurrent cartilages appear as the 

 triangular median part of a fore belt, which strengthens the floor at this part in a 

 manner similar to what is seen behind. Submesially this fore belt sends backwards 

 two ears of cartilage, then narrows a little as it passes, on its outer side, into the 

 alinasal valve. 



This is unlike any thing I have found in the other Passerines, and well worthy of 

 being recorded in figures and in words. The septum nasi (s. n) is thickened where 

 the nasal nerves burrow it postero-inferiorly ; but in this kind we lose the trabecular 

 wings, and, correlated with this deficiency, we find the alinasal cartilages closing in 

 below both in front and behind ; the fascia which unites these fore and hind belts 

 effectually hides the alinasal turbinal from view. 



In my former paper on this subject (pis. liv. & Ixii.) I showed the very remarkable 

 conditions of the nasal vestibule in Turnix and Chasmorhynchus as compared with what 

 is the typical condition of these parts in the Coracomorphse [e. g. in Corvus and 

 Buticilla) ; here, in Oriolus, we have a third modification for comparison with that 

 which is the Passerine exemplar. 



Example 65. Skull of Grey Flycatcher {Muscicapa grisola), 1st summer. 

 Family Muscicapidse. Group Oscines. 



Habitat. Great Britain. 



In this type also I have been able to show the skuil of a young bird (a fledgeling ^) ; 

 and I am able to note a very important morphological fact, namely that, whilst in the 

 typical FringillidBE (e. g. Passer domesticus, Linota cannabina) the moieties of the 

 vomer are well coalesced by the middle of incubation, here, in this species, they are 

 thoroughly distinct in young birds capable of flight. And this is of the greater con- 

 sequence inasmuch as the Muscicapidse, like the Chats (Plate LII. fig. 11) and many 



' This specimen is one, among many, for which I am indebted to Prof. Rupert Jones, F.E.S. 



VOL. x. — PART VI. No. 6. — June \st. 1878. 2 s 



