RAJIDAE 33 



Hab. Coasts of Argentina, Patagonia and Chile. 



In addition to the specimens listed above, there are 8 specimens in the British 

 Museum, 90-275 mm. in total length (width of disc 55-180 mm.), from Cape Virgins 

 and the Straits of Magellan, including the type of Psammobatis rudis. 



I have not examined any material from the coast of Chile, but have little doubt that 

 Philippi's Raja scobina represents the species described by Gunther as Psammobatis 

 rudis. Examination of mature males of this species shows that Garman's Malacorhina 

 mira is an undoubted Psammobatis, and in all probability represents the same species. 



Psammobatis microps (Gunther). 



Raia microps, Gunther, 1880, Shore Fish. 'Challenger' , p. 12, pi. iv; Berg, 1895, Anal. Mus. 



Nac. B. Aires, iv, p. 14; Evermann and Kendall, 1906, Proc. U.S. Nat. Mus., xxxi, p. 70; 



Gannan, 1913, Mem. Mus. Comp. Z00L, xxxvi, p. 359; Devincenzi, 1920, Anal. Mus. 



Montevideo (n) 1 (4), p. 127. 

 ? Raia marplatensis, Marini, 1935, Physis, XI, p. 503, fig. 



Disc broader than long, its width about § of the total length; anterior margins 

 scarcely undulated ; outer angles rounded. Vent a little nearer to tip of snout than to 

 end of tail. In the immature male there is a minute barbel-like process at the tip of 

 the snout. Snout not produced, its length 4! to 4! in width of disc; interorbital width 

 2 or 3 times the longitudinal diameter of the eye, which is about equal to or less than 

 the width of the spiracle ; length of eye + spiracle 3§ to nearly 4 in that of snout. 

 Internasal width 2 to z\ in praeoral length of snout. Mouth a little curved ; teeth more 

 or less flat and close-set ; about 40 rows in the upper jaw. Upper surface of disc mainly 

 smooth, but with areas of minute spinules on anterior margins of pectoral fins, on the 

 snout, round the eyes, and along the back; in the immature male there is a single 

 median spine in the suprascapulary region, and a series of 1 1 enlarged sharply pointed 

 spines on the tail, extending from the pelvic region to the first dorsal ; in the large female 

 there is a short row of 7 spines on the suprascapulary region and about 17 spines of 

 varying sizes on the tail; in this specimen there are no other enlarged spines on the 

 back, but the minute spinules are arranged in 3 series, the two outer ones being 

 continued on the tail ; a single large buckler-like spine near the front margin of each 

 pectoral fin ; no ocular spines in the immature male, but in the large female there are 

 2 above each orbit and 1 close to each spiracle ; lower surface smooth or with a narrow 

 rough strip along the anterior margin of each pectoral. Muciferous tubes in the nuchal 

 region very conspicuous, arranged like a fan on each side of the occiput, each opening 

 by a pore. Uniformly brownish above, white below. 



Hab. Mouth of the Rio Plata. 



Described from the type of the species, a male, 390 mm. in total length (width of 

 disc 260 mm.), and a female, 780 mm. long (width of disc 510 mm.). The mature male 

 of this species has not yet been described. Raia marplatensis (type a female of 162 mm.) 

 is probably based upon young examples of this species. 



