12 8 Memoir Sears Foundation for Marine Research 



Benthohatis marcida Bean and Weed 1 909 



Deep-sea Electric Ray 



Figure 26 



Study Material. Five specimens, 167 to 490 mm long, including the types of 

 Benthohatis marcida and B. cervina Bean and Weed 1 909, i" trawled on the continental 

 slope off South Carolina and northern and middle Florida in 353-504 fathoms, in 

 U. S. National Museum; also 60 specimens, 81 to 207 mm long, trawled in 1938 and 

 1939 by the Atlantis in 150—351 fathoms at 26 localities scattered along the northern 

 coast of Cuba."* 



Distinctive Characters. The only Rays in the western North Atlantic with which 

 Benthohatis marcida might be confused are Torpedo, Narcine, and Diplobatis. It is 

 easily separable from T. nobiliana by its much narrower protractile mouth and by the 

 minuteness of its eyes. It is distinguishable from Narcine hrasiliensis (which it resembles 

 in nature of mouth) by its degenerate eyes, by the oval shape of its caudal, by the 

 relatively much greater length of its head anterior to the spiracles, by the union of the 

 inner margins of its pelvics to their tips with the sides of the tail, by the replacement 

 of the lateral membranous folds along the tail (characteristic of the genus Narcine) 

 with low fleshy ridges, and by the softness and limpness of its body and skin (unless 

 hardened in alcohol). Its nostrils separate it from Diplohatis. 



Description. Proportional dimensions in per cent of total length. Male, 184 mm, 

 from off Matanzas, Cuba (Harv. Mus. Comp. Zool., No. 36984). Female, 430 mm, 

 off S. Carolina, Lat. 32=39' N, Long. 77°oi' W (U. S. Nat. Mus., No. 37886). 



Disc: extreme breadth 38.7, 40.5; length 42.3, 42.6. 



Snout length: in front of eyes 13.6, 13.5; in front of mouth 12.5, 14.4. 



Eyes: horizontal diameter 0.0, 0.3; distance between — , 7.5. 



Spiracles: length 2.2, 2.1; distance between 7.6, 7.3. 



Mouth: breadth 4.5, 4.9. 



Exposed nostrils: distance between inner ends 7.4, 6.3. 



Gill openings: lengths, ist 1.9, 2.2; 3rd 1.9, 2.3; 5th 1.3, 2.0; distance between 

 inner ends, ist 12.2, 11.4; 5th 7.9, 8.1. 



First dorsal fin: vertical height 4.6, 5.1; length of base 6.0, 7.7. 



Second dorsal fin: vertical height 6.0, 5.8; length of base 6.0, 7.7. 



Caudal fin: upper anterior margin 18.0, 19.3. 



Pelvics: anterior margin 9.8, 8.4. 



Distance: from tip of snout to center of cloaca 48.3, 45.7 ; from center of cloaca 

 to tip of tail 51.7, 54-3; from snout to origin of ist dorsal — , 53.7. 



Interspace between: ist and 2nd dorsals 6.0, 6.1 ; 2nd dorsal and caudal ^.^, 5.8. 



177. Albatross Sta. 2626, Lat. 32°28' N, Long. 77°2i' W, 353 fath.; Sta. 2660, Lat. 28°4o' N, Long. yi°^6' W, 504 

 fath.; Sta. 2664, Lat. 29°4i' N, Long. 79°55' W, 373 fath.; Sta. 2676, Lat. 32°39' N, Long. 77°oi' W, 407 fath. 



178. Atlantis Sta. 2938, 2980, 2981, 2982, 2983, 2984, 2999, 3305, 3387, 3388, 3391, 3392, 3410. 34i2) 34i3> 34i4) 

 3416, 3417, 3418, 3421, 3422, 3428, 3436, 3437, 3478, 3482; for precise localities and depths, see Chace (Contrib. 

 No. 274, Woods Hole oceanogr. Inst., 1940). 



