776 DESCRIPTION OF APHANTOPHRYNE, 



possessing a large, sternal plate. Although the first of these 

 two frogs is much more widely separated from Ajihantophryne 

 than are a number of Brevicipitid frogs available for dissection, 

 it is of interest, comparatively, since it shows more clearly the 

 modification of the muscles correlated with the reduction of the 

 pectoral girdle. This is the primary object of these notes. 



In addition to the muscular variations due to the widely 

 different sterna of the three species under discussion, a consider- 

 able divergence is noticed between them as regards the compara- 

 tive development, and respective size of the muscles. This is 

 mainly due to the greater or lesser development of the fore-limbs 

 which are largest in L. dorsalis. 



One of the most striking differences between L. dorsalis and 

 A. pansa, indeed, between the latter and any other Batrachian 

 that I know of, lies in the condition of the rectus abdomiiialis 

 muscle. In Limnodynastes dorsalis (Plate Iv., fig. 3, r«.), it is 

 essentially the same as in Rana escidenta* but differs somewhat 

 from that of Kaloula pulchra (Plate Iv., fig.l, o-a.) owing to the 

 absence of a linea alba in the latter. On removing the ventral 

 skin of these frogs, it is plainly visible covering the large space 

 between the inner edges of the pectorales abdominis. In A. 

 pansa, however, the rectus abdominalis is not visible without the 

 aid of further dissection. 



When the abdominal portion of the pectoral and the two 

 obliques (to be described later) have been removed, the remark- 

 able, paired condition of the rectus is revealed (Plate Iv., fig.2,ra.)- 

 Posteriorly, they are fairly broad, and in contact in the middle 

 line; but, anteriorly, they are naiTOw and quite separate medially. 

 There is, of course, no trace of a linea alba, and, as far as I can 

 be sure, there is only one, very obscure inscriptio tendinea, situ- 

 ated at about the point where the pectorales abdominis meet 

 medially. Beneath the coracoids (as viewed from the ventral 

 side) they unite with the muscle which I take to be the sterno- 

 hyoideus of each side. Towards the hinder part of the body, 



* Hoffmann, Bronn's Klass. Thier-Reichs, Bd. vi., Abth., 2, 1873-78, 

 Taf. xvii., pt. 



