346 MR. F. E. BEDDARD ON THE ANATOMY [Apr. 9, 



guppyi. It follows, therefore, that as the general bnilcl of these 

 two Fi'ogs, *. e. the proportions of the skeleton, is much the 

 same, the origin of the muscle in Megalophrys must differ from 

 that of Rana. And, as a matter of fact, it does. In Megalophrys 

 the muscle runs back into quite the pelvic region, and its posterior 

 part arises actually from the ilium. In respect of this muscle, 

 therefore, Megalophrys offers us actually what is a theoretically 

 possible condition in the ancestor of both Rana and Xenojms. Of 

 a continuous sheet of muscle such as occurs in Megalophrys, the 

 ^ntei-ior part onlj' has been retained in Rana and the posterior 



Text-fig. 98. 



Cocc.U^- 



The cESopliageal sheet of transversalis muscle in Megaloplirys nasuta. 



-al. (Esophagus. Cocc.Il. Coccjgeo-iliacus muscle, h.cf. Hyoglossus. o.d. Oviduct. 

 oes. Esophageal muscle. 



part only in Xenojms. A careful examination of this muscle in 

 Megalophrys has convinced me that no fibres escape from it on to 

 the lung or any other viscera. Its attachment to the oesophagus, 

 and to the oesophagus only, can be easily followed. The oviducal 

 membrane which it underlies is clear and transparent throughout, 

 with no muscular fibres traversing it. 



In view of the interesting differences which the transversalis 

 muscle of Megalophrys shows to the corresponding muscle of the 



