778 DESCRIPTION OF APHANTOPHRYNE, 



can only be seen by carefully angled lighting. These fibres, 

 representing the obliquus wiferwws (Plate 1 v., fig. 2, oi.), run almost 

 at right angles to those of the more superficial muscle; that is, 

 they run outwards and backwards from the middle line of the 

 ventral surface. They are so extremely thin that I cannot trace 

 their boundaries or attachments, but they appear to underlie 

 those of the more superficial muscle in toto. 



The pectortdes abdominis of A. pansa (Plate Iv., fig.2, pa.) are 

 very large, and in other respects unusual. From their origin at 

 the posterior extremity of the body, they run forward, covering 

 superficially almost the whole abdominal surface. For the greater 

 part of their length, they are in contact medially, but, a short 

 distance behind the symphysis of the coracoids, they diverge, 

 and, narrowing rapidly, enter their insertion beneath the deltoid 

 muscle. In L. dorsalia (Plate Iv., fig.3, pa.) and K. pulchra 

 (Plate Iv., fig. I, pa.) their insertion is alsooverlain by the deltoid; 

 while, in Hemisus guttatum* and Xenophrys mo7iticola,j they 

 disappear beneath the pars sternalis of the pectoral. The fibres 

 of the pectoralis abdominis run obliquely in the anterior portion 

 of the muscle, but posteriorly are almost longitudinal. The 

 muscle is characteristically thin, and separates readily from the 

 underlying obliquus externus. 



In L. dorsalis and in A', pulchra, the pectoralis abdominalis 

 presents some peculiarities worthy of notice. In both these 

 species, a remarkable modification of much the same nature 

 occurs, which, as well as being exceptional in itself, is all the 

 more noteworthy because of its presence in two such widely 

 separated frogs. Thus, we find the muscle in each case divided 

 into two distinct portions, which I have here called the portio 

 internus (Plate Iv., figs. 1 and 3, pai.) and the portio externus 

 ipae.) relative to their respective positions. 



The portio internus of the pectoralis abdotninis (Plate Iv., fig.3, 

 pai.) in L. dorsalis is fan-shaped, the fibres radiating from the 

 narrow insertion to the line of origin on the first two poststernal 

 segments of the rectus abdominalis. The line of origin is oblique 



*Beddard, Proc. Zool. See, 1908, p. 899, fig. 176. 

 tBeddard, loc. ciL, 1907, p.882, fig.231. 



