Cutaneous Veins.

The cutaneous venous system was studied only in Raja, the following description being of R. batis, but the other species appeared to be essentially similar. A lateral cutaneous vein of the usual type drains the trunk on each side, and each has parallel and dorsal to it an accessory lateral cutaneous vein. These two veins join immediately behind the scapular cartilage and pass deep to it as the subscapular vein to enter the ductus Cuvieri a short distance in front of the pectoral girdle. No dorsal or ventral cutaneous veins were observed. The extreme size of the fins and their extension forward alongside the head, result in a somewhat different arrangement of the veins in this region as compared with those of Scyliorhinus and Squatina (Marples, 1936, 1, p. 324 and 1936, 2, p. 836). In these species the dorsal pectoral cutaneous vein enters the subscapular sinus posteriorly to the scapular. In Raja a posterior dorsal pectoral cutaneous vein has this course, but in addition a large anterior dorsal pectoral cutaneous vein enters the subscapular sinus anteriorly to the scapular. It runs along the junction between the gill pouches and the propterygial cartilage on the dorsal side, and arises from branches on both the dorsal and ventral surfaces of the anterior region of the fin. It also receives branches from the head and from an extensive network over the gill pouches. The middle region of the fin is drained into two large veins, one of which enters the anterior dorsal pectoral cutaneous vein, opposite the second gill pouch, the other immediately in front of the scapular cartilage. The posterior end of the fin is drained by the posterior dorsal pectoral cutaneous vein. On the ventral side, branches from the anterior and middle regions of the fin collect into veins which pass dorsally between the fin and the gill pouches to enter the anterior dorsal pectoral cutaneous vein. The posterior ventral part of the fin is drained by the ventral pectoral cutaneous vein, which enters the lateral abdominal vein immediately behind the pectoral girdle. In the pelvic fin the pelvic transverse cutaneous vein connects the basipterygial veins to the lateral cutaneous vein as described in the previous section.