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Show 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. latissimus dorsi; and lastly, the branch elsewhere identified as the pectoralis superior, to the Mm. infraspinatus and latissimus dorsi. On the left side of the body there was no difference to mention beyond the fact that the first pair (thoracica superior) were closer together and the second pair (;thoracico-abdominalis) farther apart than 011 the right side. In Bufo mauritanicus the thoracica superior was absent from, the subclavia, its place being taken ny a small branch from the occipito-vertebralis just beyond the oesophagea. The first branch, moreover, to arise from the subclavia was not the thoracico-abdominalis but the coraco-clavicularis. A branch of this latter artery went through the coracoid foramen, but the greater portion of it passed round the M. scapular is to break up over that muscle, the posterior portion of theM.pectoralis sternal is, and the skin of the upper arm. Yery shortly after this arose the thoracico-abdominalis, distributed almost wholly to the M. obliquus internus, but sending also a twig to the M. transverso-scapvlaris major. Lastly arose the pectoralis superior supplying the M. infraspinatus and the scapula. The condition of the left side scarcely differed at all from that of the right. In this Toad there were, therefore, only three branches from the A. subclavia, In/i. boreas (text-fig. 153, p. 1029) the branches were five, their arrangement being, roughly speaking, similar to that described above for R. temper aria, The thoracico-abdominalis went almost wholly to the M. transverso-scapularis major, a small twig 011 the left side only being given to the M. obliquus internus. The most remarkable point was that the cor aco-clavicular is 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 pul mo-cutaneous arches. The condition was identically the same 011 both sides of the body. A large portion of the fourth branch went to the M. triceps brachii. The fifth branch, which was large, arose oj>posite to the latter branch and supplied the Mm. infraspinatus and deltoideus, the scapula, and the skin of the humeral region. Passing to the consideration of the Aorta abdominal is, the coeliaco-mesenteric axis arose in all cases from the left side of the point of union of the two aortic arches, that is apparently 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 traversing its substance, and the anterior one went to the mesentery. This would seem to be properly one of the A a. urogenitales, its origin having become displaced from the main |
