CIRCULATORY SYSTEM OF ELASMOBRANCHS. 445 
1. The Intestino-Mesenteric Vein [ Pl. I., 1.M.] is a small but 
nevertheless well-marked vessel that collects the blood from the 
right side of the intestine in the region of the Spiral valve and 
runs through the mesentery, from cant it receives branches, to 
open into the genital sinus. In the male it flows into the branch 
from the right testis shortly before this joins with its fellow in 
the middle line. 
3. The Anterior Parietal Veins (ant. spinal veins, Parker) come 
from the myotomes of the body between the pericardio-per itoneal 
septum and the anterior end of the kidney and flow into the 
posterior cardinal sinus. 
4. The Anterior Oviducal Sinus (ant. ov. vein, Parker) is a large 
vessel situated around the oviduct in the region -of the oviducal 
gland in the full-grown female. It is a very large sinus, quite 
separate from the posterior cardinal sinus into which it opens at 
its anterior end. In the immature female this sinus cannot be 
detected, but in the adult, and more especially when the oviducal 
gland appears to be active, it is obvious enough. 
d. The Sub-Scapular Sinus { Pls. I. & IT., $.8.] is a small sinus 
situated on the dorso-lateral aspect of the dogfish immediately 
behind the fifth gill-cleft and just ventral to the dorsal end of 
the scapular cartilage. It joins the posterior cardinal sinus on its 
dorso-lateral edge towards the anterior end by one or two small 
openings guarded bya valve. Into it opens the lateral cutaneous 
vein. As is pointed out above this vessel is generally but in- 
correctly termed the sub-clavian vein. . 
6. The Spinal and Csophageal Veins. The veins from the 
spinal cord in the body region flow into the posterior cardinal 
sinus. A few small veins from the extreme front end of the 
esophagus may also enter this sinus, but the main part of the 
blood from the cesophagus is collected by a factor of the hepatic 
portal system. 
VY. THe LATERAL VEINS. 
The Sub-Clavian Vein. 
1. The Lateral Abdominal Vein. 
2. The Iliac Vein. 
1.1. The Femoral Vein. 
2.11. The Cloacal Vein. 
3. The Rectal Vein. 
4. The Brachial Sinus. 
The Sub-Clavian Vein |Pls. I. & I1., 8.C.]. The condition of 
this vein in the embryo has already been noted. In the adult it 
is a short trunk passing from the union of the lateral abdominal 
vein and brachial sinus dorsally along the edge of the coracoid 
cartilage, and it flows into the ductus Cuvieri through a common 
opening with the inferior jugular sinus. — Its position justifies it 
