1895.] oy THE MUSCTTLAJl ANATOMY OF XEyOPXTS. 841 



portion oi deltoid in Pipa. (3) Double nature of infraspinatus in 

 Pipa. (4) Separate attachment of middle portion of triceps 

 femoris to thigh in Pipa. (5) Origin of abdominal muscles from 

 thigh in Pi^M, instead from pubis as in Rana. 



In addition, a number of smaller differences will be apparent 

 from a consideration of the foregoing account of the myology of 

 Pipa surinamensis. 



2. On the Diaphragm and on the Muscular Anatomy of 

 Xenopus, with Remarks on its Affinities. By Frank E. 

 Beddard, M.A., F.R.S., Prosector to the Society, 

 Examiner in Zoology to the University of London. 



[Eeceived October 31, 1895.] 



IIa\TLng dissected and described ' — I believe with greater detail 

 than had been done previously — the " diaphragm," as well as the 

 muscular anatomy generally, of the Surinam Toad {Pipa), I was 

 anxious to see how far there was a resemblance with the African 

 genus Xenopus (Dactylethra) ; for in spite of their wide separation 

 in space and divergent external characteristics, many naturalists 

 hold that these two genera are closely related, to which opinion 

 expression has been given by placing them in one division of the 

 Anura — the Aglossa. The opportunity of making the requisite 

 dissections has been afforded by the death of a female specimen, 

 presented to the Society a year or two since by Mr. E. Finn, F.Z.S., 

 which was brought to me directly after death, and was therefore 

 in good condition. 



§ The Diaphragm. 



Before proceeding to record the presence of various bands of 

 muscle which I believe correspond to the complicated diaphragm 

 of Pipa, I shall direct attention to certain of the viscera in 

 the neighbourhood. The lung itself is in some respects inter- 

 mediate between that of Rana and that of Pipa, as regards its 

 fixation to the body-wall. In Rana the lungs lie entirely free in 

 the coelom with the exception of their roots. In Pipa, on the 

 other hand, a considerable length of the lung is firmly attached 

 to the body-wall. Xenopus stands midway between these two 

 extremes ; a fold of peritoneum of about half an inch in length ties 

 the lung to the body-wall. There is also a pulmono-gastric 

 attachment. Beneath the lung is a deepish pocket whose right 

 and left walls are formed by these two mesenteries ; within this 

 lies the terminal section and internal orifice of the oviduct. This 

 aperture, it will be noticed from the figure (fig. 2), lies to the inner 

 side of the lung ; in Pipa the aperture of the oviduct lies quite to 

 the side (inner) of the lung, and is borne upon a special fold of 

 peritoneum, which I have illustrated in my account of the anatomy 

 of that batrachian. In Rana, on the other hand, the oviduct crosses 



^ " On some Points in the Anatomy of Pipa americana" above, p. 827. 



