'910 MR. F.E. BEDDARD ON THE ANATOMY [DeC. 15, 



•extrinsic addition to it, because of its lack of translucency. Tliis 

 part of the liyoid cartilages is, in fact, whiter and more opaque 

 than the bluish translucent cornu. This is not so evident where 

 it is so very thin (^. e. at and near to its free edge) as it is where 

 the two tracts of cartilage fuse to form the hood which has 

 already been spoken of. 



The body of the hyoid is, as already stated, long and rather 

 narrow ; it is also slightly oval in contour, is very thick, opaquely 

 white coloured, and has a swollen appearance with a convex 

 surface. It is obviously very thick without further proof by section 

 with a scalpel (text-fig. 179, B., p. 908). It therefore contrasts 

 gi'eatly with this cartilage in, at any rate, many other Frogs, where 

 it is thin and flat and even translucent. When the body of the 

 hyoid of Hemisus is divided up by a longitudinal incision it is seen 

 to present a rather complicated structure which accounts for its 

 external appearance when uninjured. Anteriorly the cartilage is 

 not particularly thick ; it underlies and is closely adpi-essed to 

 but is not continuous with a plate of bone which immediately 

 underlies the wall of the pharynx. This is not, it will be observed, 

 precisely the same thing as the ossifications which sometimes 

 occur in the body of the hyoid among Batrachians *, nor obviously 

 can it be compared to the splint of bone found underlying the 

 body of the hyoid in Pelodytes and figured by Bidewood t. We 

 have in Hemisus a plate of bone overl3dng the cartilaginous body 

 of the hyoid, from which it is completely separate and non- 

 adherent. 



This plate of bone in its turn is closely connected Math the 

 ventral wall of the pharynx. The cartilaginous plate which under- 

 lies this bone when divided longitudinally presents a remarkable 

 appearance, which is also shown in text-figure 179, B. Anteriorly 

 the cartilaginous plate is relatively thin and flat. It is behind 

 the insertion upon it of the petrohyoid that the cartilage has the 

 convex outline and swollen appearance already commented upon. 

 This turgid region is seen to be formed by a division into two 

 plates of the cartilaginous hyoid which do not absolutely meet but 

 come into the closest contact possible short of fusion posteriorly. 

 Imbedded in the space between the two layers of the dichotomously 

 divided sheet of cartilage is a lenticular mass of a softish con- 

 sistency and a spongy appear-ance. I am unable to suggest what 

 this is, unless it is developing bone. Though the above descrip- 

 tion is incomplete in this, it is obvious from the facts which I 

 have been able to ascertain definitely that the hyoid complex in 

 Hemisus is very remarkable. 



There are other Frogs than the Engystomatid in which the 

 hyoid apparatus is in certain respects like that of Hemisus. I 

 have already directed attention to the likenesses shown in the 

 hyoid of Breviceps. The thin layer of rather different-looking 



* E. g., Sappia sp., Cyclorliamphus marmoratus, &c., Parker, Phil. Trans. 1881. 

 t lioc. cit. pi. XXXV. fig. 10. 



