MUSEUM OF COMPARATIVE ZOOLOGY. 221 



EXPLANATION" OF FIGURES. 



REFERENCE LETTERS. 



a. artery (in Fig. 2, also auricle). 



a. c. arcus cephalicus. 



a. i. anterior innominate artery. 



an. anastomotic branch of first efferent branchial artery. 



a. pi. artery connecting pituitary plexus with hypophysis plexus. 



6. a. bulbus arteriosus. 



br. brachial vein. 



c. cranial aorta (in Fig. 7, the cavity of this vessel). 



c. a. conus arteriosus. 



c. c. anterior carotid commissure (art. com. ant. D. S.). 



cent. vertebral centrum. 



ch. chorda dorsalis. 



cce. mes. cceliaco-mesenteric artery. 



cor. coronary artery (-+- hypobranchial trunk). 



c. p. art. profunda cerebri. 



c. p. a. posterior carotid commissure (art. com. post. D. S.) 



c. c. cardinal sinus. 



c. sh. chorda sheath. 



ct. cartilage of the basis cranii, c', c" , c'" , three layers of basis cranii. 



ct. sk. cartilaginous sheath of chorda and cranial artery. 



c. v. cardinal vein. 



d. dorsal aorta (posterior to k). 



d. m. dura mater. 



e. c. external carotid artery. 



e. ex. elastica externa of notochord. 



g. median groove in ventral surface of basis cranii. 



H. Hyoid arch. 



A. v. hepatic vein. 



hy. hypophysis. 



t. c. internal carotid artery. 



i. c. f. internal carotid foramen. 



i. j. v. inferior jugular vein. 



k. cephalic aorta. Kopfaorta, arteria spinalis impar Hyrtl, arteria ver- 



tebralis impar Miiller. 



Id. calcareous incrustation. 



