124 Memoir Sears Foundation for Marine Research 



lb. Disc wider than long; tips of dorsals and caudal rounded; anterior margin of 

 pelvics concealed by pectorals. ommata (Jordan and Gilbert) 1890. 



Eastern Pacific from Gulf of California to 

 Panama. 



Diplobatis pictus Palmer 1950 



Figure 25 a 

 Study Material. None. 



Distinctive Characters. The closest relatives of D. pictus in the western Atlantic are 

 Benthobatis marcida. Torpedo nobiliana, and Narcine brasiliensis. It may be separated from 

 B. marcida by its relatively large eyes, from T. nobiliana by the strongly convex anterior 

 outline of its disc and from N. brasiliensis^ which it most closely resembles, by its divided 

 nostrils and concealed teeth (p. 123). 



Description. Proportional dimensions in per cent of total length. Female, 137 mm 

 long, holotype, from off Georgetown, British Guiana (British Museum [Natural 

 History]). 16' 



Disc: extreme breadth 46.7; length 47.5. 



Snout length: in front of orbits 10.9; in front of mouth 13.1. 



Orbits: horizontal diameter 3.6; distance between 6.6. 



Spiracles: length 3.3; distance between 6.6. 



Mouth: breadth 6.6. 



Nostrils: distance between inner ends 5.1. 



Gill openings: lengths, ist 1.5; 3rd 1.8; 5th 1.5; distance between inner ends, 



ist 13.9; 5th 9.5. 

 First dorsal fin: vertical height 8.0; length of base 6.6. 

 Second dorsal fin: vertical height 8.7; length of base 6.2. 

 Caudal fin: upper anterior margin 13.9; lower anterior margin 13.2. 

 Pelvics: anterior margin 14.6. 

 Distance: from tip of snout to center of cloaca 51.8; from center of cloaca to 



tip of tail 48.2. 

 Interspace between: ist and 2nd dorsals 3.6; 2nd dorsal and caudal 5.8. 



"Disc obtusely rounded, spade-shaped, its greatest width being opposite the last 

 gill-cleft. Margin of snout elliptical. Length of disc equal to its greatest width, con- 

 tained 2.1 times in total length and 1.9 times in length to caudal notch. Interorbital 

 width twice in length of snout (preocular). Spiracles, greatest length of which is con- 

 tained twice in interspiracular width, situated Immediately behind the orbits. Posterior 

 margin of each spiracle fringed with 7-8 small papillae. Interspiracular width con- 

 tained twice in pre-oral length of snout plus nasal curtain. Anterior aperture of nostril 

 exposed, separated by a bridge of tissue from the concealed posterior aperture. Nasal 

 curtain much wider than long, Its free edge slightly crenulated. Mouth narrow, pro- 



167. These proportions were furnished by G. Palmer, Dept. of Zoology, British Museum (Natural History). 



