222 BULLETIN OF THE 



m. muscle. 



me. membraneous wall overarching c near its anterior end. 



m. s. arteriae musculo-spinales. 



VIS. arteriae musculo-spinales of the head. 



n. nasal artery. 



n. p. neural process. 



0. ophthalmic artery. 



p. palatine artery (= maxillary of Parker). 



p. c. e. art. post, cerebri ext. D. S. 



p. c. I. art. post, cerebri int. D. S. 



p. c. s. precaval sinus. 



p. pi. pituitary plexus. 



pt. pituitary space. 



r. c. subdural rete mirabile. 



r. c. V. right cardinal vein. 



r. p. rete mirabile profunda cereori D. S. 



s. cl. subclavian artery. 



s.j.v. superior jugular vein. 



sp. anastomosing branch to spiracle. 



s. V sinus venosus. 



tr. tropeic vein = lateral abdominal vein. 



tr. b. fibrous trabeculae crossing the channel of c". 



tr. c. transverse canal of pituitary region. 



tr. p. transverse process. 



r. ventricle. 



V. a. ventral aorta. 



vase. vascular layer. 



I.-IX. First to ninth pairs of aortic roots (arches). 

 1-6. First to sixth pairs efferent branchial vessels. 

 l'-6'. First to sixth pairs afferent branchial vessels. 

 l"-5". First to fifth visceral arches. 



Fig. 1. A sketch of a dissection of the efferent branchial vessels and the result- 

 ing aorta of Chlamijdoselachus anguineus, natural size. On the right of the figure 

 the vessels are sketched in the outline of the roof of the mouth, to the point of 

 emergence from the tissue surrounding the proximal ends of the gill arches indi- 

 cated on the left oval outhnes. The left internal carotid artery is not shaded, 

 and is sketched for a short distance only to show its course in the chiasm, at 

 which point the cephalic aorta is broken for the sake of clearness. The end of the 

 cranial aorta, and its branches connecting it with the pituitary plexus, are drawn 

 somewliat enlarged. 



Fig. 2. A semidiagrammatic figure of a portion of the vascular system of the 

 same fish, showing the relations of the arterial and venous vessels, as seen from 

 the left side. Approximately natural size. At * the coronary artery is cut off, 

 nor are many of its branches shown. The venous vessels, heart, and ventral aorta 

 are left unshaded. The common and internal carotids have been displaced up- 

 wards, and the anastomotic branch broken for sake of clearness. 



