1014 MR. L. R. CRAWSHAY ON THE ARTERIAL [DeC. 11, 



foramen ; fourthly, the largest branch distributed for the most 

 part to the skin of the upper arm and under the pectoral girdle 

 and to the M. latisshnus dorsi ; and lastly, the branch elsewhere 

 identified as the pectoralis superior, to the Mm. i7ifraspinaUis 

 and latissimus dorsi. On the left side of the body there was 

 no difierence to mention beyond the fact that the first pair 

 [thoracica supei'ior) were closer together and the second pair 

 (thoracico-ahdoininalis) farther apart than on the right side. 



In Bufo itnauritanicus the ihoracica superior was absent from 

 the subclavia, its place being taken by a small branch from 

 the Gccijnto-vertehrcdis just beyond the oesophagea. The first 

 branch, moreover, to arise from the subclavia was not the 

 thoracico-ahdominalis but the coraco-clavicidaris. A branch of 

 this latter artery went through the coracoid foramen, but the 

 gi'eater portion of it passed round the Af. scapidaris to break up 

 over that muscle, the posterior portion of t\\e M. pectoralis steroialis, 

 and the skin of the upper a,rm. Very shortly after this arose the 

 thoracico-ahdominalis, distributed almost wholly to the j1/. ohliquus 

 internus, but sending also a twig to the M. transverso-scaptdaris 

 'major. Lastly arose the pectoralis supei'ior supplying the 

 21. infraspinatus and the scapula. The condition of the left side 

 scarcely difiiered at all from that of the right. 



In this Toad there were, therefore, only three branches from 

 the A. subclavia. 



In jB. horeas (text-fig. 153, p. 1029) the branches were five, their 

 arrangement being, I'oughly speaking, similar to that described 

 above for R. temporaria. The thoracico-ahdoininalis went almost 

 wholly to the M, transverso-scapidaris major, a small twig on the 

 left side only being given to the M. ohliquus internus. The most 

 remarkable point was that the coraco-clavicidaris did not arise 

 independently, but in common with quite a new artery which shortly 

 separated from it and ran direct to the gland which has already been 

 referred to as lying upon the distal ends of the systemic and 

 pulmo-cutaneous arches. The condition was identically the same 

 on both sides of the body. A large portion of the fourth branch 

 went to the M. triceps h'achii. The fifth branch, which was large, 

 a,i-ose opposite to the latter branch and supplied the Mm. infra- 

 spinatus and deltoideus, the scapula, and the skin of the humeral 

 region. 



Passing to the consideration of the Aorta ahdominalis, the 

 coeliaco-mesenteric axis arose in all cases from the left side of the 

 point of union of the two aortic arches, that is apjDarently as a 

 continuation of the left arch. 



In Bufo mauritanicus, a vessel about as large as the A. lienalis 

 arose from near the origin of the coeliaco-mesenteric axis and ran 

 back in the mesentery, dividing into two branches, of which the 

 posterior one extended to the anterior border of the left kidney 

 without travei'sing its substance, and the anterior one went to 

 the mesentery. This would seem to be properly one of the 

 Aa. ibrogenitales, its origin having become displaced from the main 



