848 MR. r. E. BEDDABD ON THE [DeC. 3, 



magnus, such as is figured by Ecker^ in Rana esculenta. The 

 muscle ends in a thin rounded tendon, whose relations with the 

 sartorius have been already referred to. 



Rectus internus, major et minor. In Rana and in Pijya there are 

 two perfectly distinct recti interni ; in Xenopus there are also two. 

 The larger of the two, which I take to be the major, overlaps the 

 semitendinosus, and is overlapped by the minor. The latter lies 

 entirely superficial to the major and covers its posterior half. 



On the outer side of the thigh the only muscles visible without 

 a dissection are the Semimembranosus and the outer part of the 

 Triceps femor is. The Biceps is largely concealed by the vastus 

 e,vternus ; the great backward prolongation of the Latissimus dorsi — 

 to which I have elsewhere^ directed attention as a point of resem- 

 blance between Xenopus and Pij^a — completely covers the glutceus 

 and is attached to the thigh. 



The GlutcBus, after removal of the latissimus dorsi, is seen to 

 be a very extensive muscle, much larger than in Rana. It is 

 inserted by a flat tendon and also by muscle-fibre ; between its 

 insertion and the head of the femur is to be seen a portion of the 

 'pyriformis, which is nearly but not completely covered by it. 



The Psoas is a fleshy muscle with a long insertion. 



In order to eifectively display the pyriformis, the glutceus must 

 be removed or slit up the middle, and the two halves reflected. 

 The pyriformis is then seen to be a large bipiniiate muscle ending 

 in a stout tendon, attached nearer to the head of the femur than 

 glutceus. 



§ Affinities of Xenopus. 



The noteworthy peculiarities in the musculature of Xenopus as 

 compared with Rana are : — 



(1) The large size and attachment of the Sartorius. 



(2) The single-headed Semitendinosus. 



(3) The enormous extension backwards of the Latissimus dorsi. 



(4) The absence of the Pecforo-cutaneus. 



(5) The attachment of the muscles covering the abdomen to the 



fascia covering the thigh. 



(6) The presence of a sheet of muscle below the Mylohyoid 



which joins the Deltoid. 



(7) The great extent of the Pectorcd, which completely covers the 



Sternoradialis. 



(8) The large size of the Glutceus. 



(9) The existence of a special muscle running from the ilium 



to the lung and oesophagus. 



There are also, as will be gathered from the foregoing account 

 of the unisculature of the animal, other differences from Rana of 

 less importance. 



Of the difEerences enumerated above, (3), (4), (5), (6), and (9) 



» Lnc. cit. p. 100, fig. 83, st'". 



* " On some Points in the Anatomy of Pipa americana,'' above, p. 834. 



