No. 462.] LATERAL VEIN OF SKATE. 357 
trunk, from its position and size, is doubtless entitled to the 
name, femoral vein. It receives one large branch from the 
median side of the basipterygium. The remainder of its 
branches are distributed upon the external side of the basi- 
pterygium, collecting the blood from much the greater portion 
of the fin. A second and considerably smaller vein emerged 
from the fin on the anterior side of the pre-axial fin-ray, corre- 
sponding with the vein found in III and with the anterior one 
of the two veins found in I. The branches of this vein were 
distributed around the large pre-axial fin-ray, the main axis of ' 
the vein lying along the anterior side of the ray. 
The third one of the three veins mentioned as entering the 
lateral vein from the pelvic fin was a very small vessel which 
lay just anterior to the iliac process of the girdle. 
VI. Raia erinacea: small female. 
1. Renal portal system injected, via the caudal vein, with 
blue celloidin. 
A trace of the celloidin appeared in the right postcardinal 
vein. 
2. Right lateral vein injected posteriorly with red celloidin. 
The mass entered a fine network of vessels on the cloaca and 
rectum, passed through minute vessels lying along the ventral 
margin of the mesorectum, and a small quantity of it collected 
in the rectal extension of the cardinal sinus. 
By dissection, the lateral vein was traced up to the wall of the 
cloaca (see Fig. 3), where, at a point nearly in the same trans- 
verse plane with the anterior end of the external cloacal aper- 
ture, it divided into two branches. Each of these immediately 
broke up into fine branches which anastomosed with vessels of 
the network. On the dorsal wall of the rectum and just behind 
the rectal gland, the network resolved itself into a system of 
fine vessels (Fig. 3, A and B, vz.) lying nearly parallel with one 
another, frequently anastomosing, and converging forward into 
fewer and larger vessels in such a way that there was a gradual 
transition from the rectal network into the single very narrow 
lumen of the posterior tip of the cardinal sinus. 
No veins from the pelvic fin were injected. 
