898 MR. F. E. BEDDARD 0>r THE ANATOMY [Dec. 15, 



internal svirface of the ilia and their nuiscles are exj)osed, as I 

 have recently figured * in the genera Megcdophrys, Rana, Pelohates, 

 and Geratophrys. The conditions observ^able in Hemisus when 

 a dissection of this kind is made are more like those of Ceratoplirys 

 than those of any of the other genera to which I have just i^ef erred. 

 The ilium is exposed for the greater part of its length and devoid 

 of muscular covering, for the ilio-coccygeal origin does not extend 

 at all over the ventral surface of the bone. 



The ilio-lumharis arises towards the anterior end of the ilium, 

 exactly in the way in which I have figured it in Ceratoplirys. 

 It is, however, a rather more solid muscle and passes up to the 

 origin of the cesophageal muscle t without a break except for 

 tendinous intersections which correspond to the transverse 

 processes of the successive vertebree. Moreover, it abuts closely 

 upon the centra of the vertebra?, at any rate anteriorly. There 

 is no long lateral slij) of this muscle as in the Pelobatidfe +. 



§ Ventral Musculature. 



The two pectorales abdominis differ from those of many Frogs 

 in that they meet in the middle line ventrally. The rectus 

 abdominis absolutely ceases to be visible with their origin, and is, 

 in fact, anteriorly to this line covered by them, a peculiarly 

 strong inscriptio tendinea forming the boundary line between 

 the two muscles. Another peculiarity of this inscriptio tendinea 

 besides its sti'ength and toughness, which is doubtless in relation to 

 the importance of the pectoi'alis attached to it, is the fact that this 

 tendinous seam is firmly attached to the skin. So firm and so 

 direct {i. e. not through a special septum such as those which 

 divide the other subcutaneoiis Ij^mph-spaces) is this connection 

 that some filjres of the muscles concerned have the appearance 

 of arising from the skin. The two pectorales abdominis ai'e 

 not only continuous at their origin from this tendinous seam and 

 septum, their fibres are nearly in contact for some little space 

 in front of this ; for there is a prolongation forwards of the seam 

 at right angles to the rest, from which the innermost fibres of each 

 pectoralis abdominis ari.se. This is not, however, continued far 

 towards the sternal region. A triangular or, indeed, almo.st 

 V-shaped space is left between these two pectorales abdominis 

 and the pars sternalis anteriorly, as is shown in the figure 

 (text-fig. 176), which is uncovered by any muscular layer and 

 where the posterior region of the pectoralis sternalis is exiwsed. 



In the middle ventral line of the body the septum between 

 the pectoralis abdominis and the rectus abdominis is pretty 

 well at right angles to the longitudinal axis of the body. 

 Laterally the line of origin of the pectoralis curves more and 

 more anteriorly, so that at the sides of the body the origin of the 



* P. Z. S. 1907, p. 332, text-fig. 93, p. 333, text-fig. 94, &c. 

 t For which see p. 915. 

 J P. Z. S. 1907, p. 905. 



