36 ALLEX 



veins. An excellent account of the embryolog}' of the heart 

 and blood vessels was given by Hoffman (39) in 1S93. In 

 Vogt and Yung's Anatomic, vol. 2, there is found a brief, but 

 excellent account of the circulatory system of the perch, with 2 

 colored plates. T. J. Parker (61) in his Zootomy, 1895, gives 

 the general outline of the circulation in the skate. Raja nasuta^ 

 with 2 figures, and also a similar description and one figure on 

 the circulation of the cod, Gadus morrhtia. In the first few 

 pages of Allis' paper on Ainia (3), there is a detailed account 

 of the circulation in the head region, illustrated by several 

 beautiful colored plates. To Jordan and Evermann (45) in 

 1898, we are indebted for a systematic arrangement of the fishes 

 and fish-like vertebrates of North America. In 1900, Allis (4) 

 published a complete account of the development of the pseudo- 

 branchial circulation in Ainia, and lastly, Briinning (10) in the 

 same year was the first to work out in any detail the physiology 

 of the blood vascular system of fishes. To this list might be 

 added the general comparative anatomies of Gegenbour (26 and 

 27) and Wiedersheim (86 and 87). 



SECTION II. TEXT. 



IV. GENERAL SURVEY OF THE BLOOD VESSELS IN OPHIODON. 



Since the blood of a fish passes around in a circle, it matters 

 but little where we begin. A simple glance at PI. I, fig. i, will 

 give an idea of the general course of the blood. The entire 

 venous blood is poured into the simis vcnosus (Pis. I and II, 

 figs. I and 12; Sin.Ven.), through 6 large sinus-like vessels. 

 From the rear come the hepatic veins (Pis. I and II, figs, i and 

 12 ; Hep. v.), which through the' capillaries of the liver receive 

 the portal veins (PI. I, figs, i, 6, and 11 ; L. and R.Por.V.), 

 bringing the venous blood from the viscera ; and the ventral 

 veins (PI. I, fig. 12 ; L. and R.Ven.V.) conveying the blood 

 from the ventral or pelvic fins and the body walls. From either 

 side, the sinus venosus receives 2 large lateral trunks. The 

 posterior ones or subclavian si)iiiscs (PI. II, iig. 12 ; Sub.S.) 

 are the smaller, containing venous blood from the outer or 

 abductor muscles of the pectoral fins ; and the anterior or larger 

 ones are the precaval veins or ductus cuvieri (P\. II, lig. 12; 

 Proc.V.), which receive the venous blood from the rest of the 



