902 ME. F. E. BEDDARD OX THE ANATOMY [DeC. 15,; 



have just referi-ed to in liana guppyi and Pipa * as the pectoralis 

 minor. It arises (text-fig. 177, s.', p. 901) from the moi^e internal 

 part of the coracoid not only below the pectoralis sternalis, but 

 from the opposite (^. e. the dorsal) side of the coracoid bone. It 

 arises by several partly separate strands, is fan-shaped, and rapidly 

 narrows to a cylindrical muscle, which is inserted on to the opposite 

 side of the humerus to the pectoi-alis, and is doubtless a muscle of 

 antagonistic action. 



In front of this lies the third muscle of the sei-ies which I am now 

 considering (text-fig. 177, s.). It is a short rather broad muscle 

 arising from the humeral half of the coracoid. It is attached to 

 the humerus just below the insertion of the first-described of the 

 three muscles belonging to the present series. I think that there 

 can be little doubt that it really corres^Donds to the coraco-humeralis 

 of Rana. 



The obliquus is quite extensive on the dorsal surface of the 

 body, the fibres having precisely the same direction as those of 

 the obliquus externus in Rana, i. e. obliquely from before back- 

 wards and outwards. When the animal is pinned in a dissecting- 

 dish with the ventral side downwards, the whole of the flanks 

 are seen to be occupied by this muscle up to the large vacuity 

 posteriorly occupied by the saccus iliacus. Dorsally the fibres 

 originate laterally of the ilia and expanded sacral transverse 

 processes from the tough aponeurosis Avhich covers the dorsal 

 musculature loosely, and is attached by a downward band to the 

 ilia and sacral transverse processes before it becomes confluent 

 with the obliquus externus. Posteriorly the muscle appears to 

 end in a slightly thickened concave margin at the saccus iliacus. 

 This ending, however, is only apparent ; there is a folding over 

 exactly such as will be described in the case of the rectus in the 

 pubic and femoral region, but less in extent, and caused in exactly 

 the same way, or, at any rate, correlated with an anatomical fact 

 of the same nature. For in the muscle now being described there 

 is a firm insertion along the bend of the muscle-layer of the 

 dorsal wall of the iliac lymph-sac. The fold in this dorsal region 

 of the obliquus is by no means so deep, however, as is that of the 

 rectus abdominis ventrally. It is plain all the same from following 

 them out that the fold in question is perfectly continuous from 

 the ventral region to the dorsal, and it follows therefore that 

 there is no strict demarcation between the rectus abdominis and 

 the obliquus externus in this Frog. That is to say, there is no 

 line of demarcation between the deeper flap of the i-ectus and the 

 obliquus externus. The superficial flap of the rectus, as already 

 said, ends upon the skin. The two parts of the muscle are thus 

 nearly at right angles here, and the posterior sheet runs 

 almost dorso-ventrally, forming the anterior boundary of the. 

 iliac lymph-sac and exposed by cutting optn one of the septa 



* A redissection of the muscles in question in Bana gwppyi shows the presence of 

 the "'pectoralis minor " in that Frog, as I have asserted. 



