1907.] ANATOMY OF THE PSLOBATTD.E. 877 



surface. The ilio-coccygeal is cut across obliquely. The ilium 

 is seen clearly, and to the outside of it runs the narrow muscle 

 belonging to the ilio-lumbar complex which I have had occa- 

 sion to describe as probably characteristic of the Pelobatidse. 

 Outside of this again is seen the broad and thin transversalis 

 muscle with its cut edge divided across its fibres, i. e. parallel to 

 the long axis of the body of the frog. Outside this, again, is the 

 obliquus muscle. It will be seen that the transversalis is not fan- 

 shaped and that its fibres are nowhere collected into a thick 

 bundle as in Megaloplirys montana. On the contrary, the muscle 

 obviously ends in a series of digitations near to the end of the 

 obliquus fibres, and these are connected with the pubis only in- 

 directly by the tendinous aponeurosis represented in the drawing- 

 referred to (text-fig. 229). The insertion of the transversalis on to 

 the aponeurosis is a very long one : it reaches, in fa,ct, a little way 

 anteriorly to the pubis and back nearly as far as the symphysis. 



In both species therefore the attachment of the transversalis 

 muscle lies outside of the long ilio-lumbai* muscle., which, I may 

 take this opportunity of remarking, is just as well developed in 

 Meyaloplwys 'inontana as it is in M. nasuta. ISTor is there, so far 

 as I could see, any attachment to any vertebree comparable to the 

 equivalent of this muscle in Rana, Ceratophrys, &c. In fact, in 

 Megalo'phrys the transversalis seems to have preserved a primitive 

 arrangement as one of the covering sheets of the body unconnected 

 directly (only through aponeurosis) with any bones. A further 

 specialisation of this muscular sheet would lead to the conditions 

 observable in Sana &c. on the one hand, and in Pipa and Xenopus 

 on the other. There are in fact no reasons that I can detect from 

 an examination of the transversalis and neighbouring muscles 

 in Megcdophrys montana, for separating it widely from its supposed 

 congener Megaloplirys nasuta. 



The following is a tabular statement of the difterences existing 

 between the two species. The resemblances I shall point out 

 later, when considering the allied forms Xenop)lirys and Lepto- 

 hrachium. 



Megaloplirys nasuta. Megaloplirys montana. 



(1) Tympanum invisible. Tympanum quite distinct. 



(2) Palpebral processes very large; Palpebral processes small ; "nose-leaf " 



"nose-leaf" present. rarely present. 



(3) Conical tubercles on back only three. Conical tubercles numerous. 



(4) Index finger considerably longer Index finger only just longer than 



than second. second. 



(5) Vomerine teetli betvreen clioanse. Vomerine teeth behind choanai. 



(6) Omosternum less rudimentary. Omosternum more rudimentary. Ster- 



Stei-num one fourth body-length, num one third body-length, with 



with large posterior cartilaginous small posterior cartilaginous epi- 



epiphysis. physis. 



(7) Vertebra procrelous. Vertebraj opisthoccelous *. 



(8) Sacral vertebra completely fused Sacral vertebra articulating with adjoin- 



with coccyx. ing coccyx. 



(9) Anterior processes of hyoid parallel. Anterior processes of hyoid convergent. 



I have verified these facts in the case of the specimen described here. 



59* 



