CIRCULATORY SYSTEM OF ELASMOBRANCHS. 447 
condition in R. erinacea and R. levis, where paired vessels from 
the end of the rectum run straight into the lateral abdominal 
veins. 
4. The Brachial Sinus (Br. vein, Parker) (Pls. I. & IT., B.] 
collects blood from the pectoral fin and passes along near its 
posterior edge. It leaves the fin and penetrates the body-muscles 
to open into the lateral abdominal vein on the posterior edge 
of the coracoid cartilage. 
The Cutaneous Veins. 
1. The Lateral Cutaneous Vein. 
9. The Posterior Ventral Cutaneous Vein. 
1. The Lateral Cutaneous Vein (Parker) [ Pls. 1. & Int, 10) 
originates far back in the tail, and forms a well-marked vessel 
running to the region of the pectoral fin, in the connective tissue 
immediately underlying the lateral-line canal. Here it passes 
inwards and opens into the sub-scapular sinus. Parker describes 
anastomoses between it and the caudal vein, and such anastomoses 
ean be found in sections of embryos of 56 mm., but I have been 
unable to inject and display them by ordinary dissection. 
2. The Posterior Ventral Cutaneous Vein (Parker) can be seen in 
transverse sections both of embryos and of adult fish. It runs 
forward embedded in the connective tissue in the mid-ventral 
line from the tail, forms a loop around the anal fin, and forks in 
the region of the cloaca. A similar vein is to be found under the 
eutis in the median line of the abdomen, and this doubtless 
corresponds to the anterior ventral cutaneous vein of Parker, but 
the exact relations of its anterior and posterior ends could not be 
ascertained as it is too small for injection. 
Serial sections through embryos of 37 and 56 mm. length have 
been studied, and the general arrangement of these cutaneous 
vessels is apparently similar to that in Mustelus as described by 
Parker. They are not dealt with in detail here as they have only 
been followed in the above sections, and they cannot be studied in 
the adult by ordinary methods of injection. 
he ventral cutaneous veins are too small to inject successfully, 
even with a hypodermic syringe, and the dorsal cutaneous vein is 
barely visible to the naked eye. 
VI. THe SuB-INTESTINAL VESSELS. 
A. The Hepatic Portal Vein. 
1. The Posterior I ntestinal Vein. 
9. The Posterior Lieno-gastric Vein. 
9. i. The Posterior Splenic Vein. 
9. ii. The Median Gastric Vein. 
8. The Pancreatic Veins. 
