1907.] ANATOMY OF THE PELOBATID^. 875 



nasibta I have already described its general characters. The 

 proportions of the length to the breadth of the bony shaft in its 

 naiTowest region do not appear to differ greatly from those of 

 M. montana. The diameter was rather more than 1 mm., perhaps 

 1| mm., about a twenty-fourth part therefore of the length. 

 This is not widely different from the proportions exhibited by 

 M. montana. 



§ Hyoid and its Musculature. 



I reserve for later discussion * certain facts relative to the hyoid 

 cartilages and the muscles attached thereto. In this place the 

 differences between the two Frogs assigned both of them to the 

 genus Megalojyhrys will be considered. In examining the hyoid 

 cartilages one obvious difference will be seen to distinguish the 

 present species from Megalophrys nasuia. In the latter (c/. the 

 figxire illustrating my paper upon that Pelobatid f) the two pro- 

 cessus anteriores of the body of the hyoid run anteriorly on the 

 whole parallel to each other, with but a slight inclination towards 

 the middle line, ^. e. towards each other. Their extremities are 

 in fact separated by quite 9 or 10 mm. across the middle line of 

 the throat. In Megalophrys montana the processes in question, 

 as in Pelobates and Pelodytes +, incline greatly towards each other 

 and are finally only separated by the space of 1 mm. or but 

 slightly more, 



§ Q^sopliageal Portion of the Transversalis Muscle. 



This muscle is quite as conspicuously developed in Megalophrys 

 'montana (text-fig. 233, p. 886) as it is in M. nasuta. But there 

 are certain difterences in detail between these two species. 

 Anteriorly at the sej)tum defining the abdominal cavity (the 

 cervical aponeurosis) its fibres lie side by side with those of the 

 obliquus externus, and no line of division can be detected between 

 the two muscles. Continuing on an imaginarj- line from the 

 point where the two muscles are really distinct, it would appear 

 that the transversalis is only inserted upon the oesophagus and 

 is not connected with the cervical aponeurosis or the lungs at 

 their root. The oviduct runs across it ; but I cannot find that 

 any of its fibres are deflected into the membrane supporting that 

 tube. The muscle is pretty stout_ and fairly thick. Crossing 

 the anterior end of the pelvis, and of course the ilio-coccygeal 

 muscle arising therefrom, not far from its anterior end, as shown 

 in the accompanying figure (text-fig. 233, p. 886), the fibres of the 

 transversalis gather themselves together to form a thicker tract of 

 the muscle like the laths in the handle of a fan. This is the 

 origin of the muscle, and it passes back for a considerable distance 

 completely free of the ilium, to be finally attached away from that 



* Infra, p. 892. t P. Z. S. 1907, p. 341, text-fig. 97. 



X See figs, bj' Bouleiiger in ' Tailless Batrachia of Europe,' and Kidewood, P. Z. S. 

 1897, pi. XXXV. 



Proc. Zool. Soc— 1907, No. LIX. 59 



