314 Memoir Sears Foundation for Marine Research 



Generic Characters. Rajidae with pectorals of ordinary form, without spatula-like 

 lateral processes. The outer margins of the pelvics are so deeply notched that the 

 anterior division, which arises independently from the lower surface of the disc some 

 distance inward from the edge of the latter, is entirely cut off from the remainder of 

 the fin as a separate limb-like structure. The two or three radial cartilages that are 

 ordinarily borne near the anterior end of the basipterygial cartilage are lacking, and 

 the gap resulting from their absence corresponds in position to the gap seen externally 

 between the anterior and posterior subdivision of the pelvic fin. Anterior subdivision 

 of pelvics slender, subcylindrical, tapering toward tip, stiff proximally but softer distally, 

 consisting of three articulated segments and hence flexible at two or three points as 

 well as at its base (stoutness of musculature toward its base suggests considerable 

 powers of movement); its support is maintained by the first stout radial and two or 

 three slender radials which are articulated directly to the outer extremity of the pelvis. 

 Posterior lobe of pelvics finlike, supported by about 1 8 radials. Rostral cartilage rigid, 

 narrow, extending nearly or quite to tip of snout. Tips of anterior pectoral rays falling 

 well short of tip of rostral cartilage. Characters otherwise as in Raja. 



Remarks. The limb-like modification of the anterior subdivisions of the pelvics 

 of Cruriraja is the outstanding feature of the genus. In this respect it appears to be 

 unique among batoids so far as is known, except for the little-known genus Anacantho- 

 hatis von Bonde and Swart 1924,18 from Natal, in which the anterior subdivisions of 

 the pelvics are described as "leg-like" and "segmented" (as in Springeria, p. 328), and 

 except for one genus of Electric Rays (Typhlonarke), family Narkidae. The function 

 of the pelvic limbs is not known ; they may be tactile, as are the feeler-like ventrals 

 of the hakes (Urophycis), or they may assist in the progress of their owners over 

 the bottom. 



Size. The two known species from the Atlantic are small, males having large and 

 fully developed claspers at lengths no greater than 300-325 mm. But the maximum 

 size of the Indian Ocean representatives is not known, for no mature specimens were 

 included among the few that have been seen. 



Habits and Range. Nothing whatever is known of the life histories of the members 

 of the genus, except that they are confined to moderately deep water, the recorded depths 

 of capture ranging from 280-425 fathoms for the Atlantic (p. 319) and from 298- 

 470 fathoms off the Natal Coast. 



Key to Species 2" 



I a. Interspace between first and second dorsals about 1.5 times as long as base of 

 first dorsal. atlantis Bigelow and Schroeder 1948, p. 315. 



I b. Interspace between first and second dorsals not more than about half as long as 

 base of first dorsal. 



19. Fish. Mar. biol. Surv. S. Afr., Rep. 3 (1922), Spec. Rep. 5, 1924: 18, pi. 23. 



20. Kaja andamanka Lloyd 1909 (Mem. Indian Mus., 2 [3], 1909: 140; 111. Zool. Investigator, Fishes, 10, 1909: pi. 46, 

 fig. 2) may prove to be a Cruriraja also, when the nature of its pelvic fins is known definitely. 



