NO. US2. ARGENTINA FISHES— EVERMANN AND .KENDALL. 71 



6. PSAMMOBATIS SCOBINA (Philippi). 



RAYA. 



Raya scobina Philippi, Weig. Arcliiv fiir Naturg., XXIII, 1857, p. 270, Chile. 

 Psammobatis ™c/(S Gunther, Cat., VIII, 1870, p. 470, Sandy Point, Chile. — Berg, 

 Anal. Mus. Nac. Buenos Aires, IV (2d ser., I), 1895, p. 14 (Mar. del Plata). 

 Raja scobina Philippi, Anal. Mus. Nac. Chile, Zool., 1892, p. 2, pi. i, fig. 1 (Chile). 



Berg records Psarmnohatis rtidis Glinther, in the .synon3^my of which 

 he doubtfully includes Baja scohma Philippi. Regarding- it he says: 

 "This species, which, according to Gunther, is identical with Raya 

 scohina Philippi of the Pacific coast of Chile, is comparatively rare. 

 The longest of those examined was 28 cm. The number, form, and dis- 

 tribution of the spines and sharp tubercles, as well as the coloration 

 and the extent of the pale spots, vary greatly in this ray." 



Giinther's t^^pe of his species, Psammobatis rudis^ was an immature 

 individual only 7 or 8 inches long, some of the characteristics of which 

 were the perfectly circular disk; snout short, overlapped b}^ the ante- 

 rior portions of the pectoral fins; tail with no distinct terminal fin, and 

 each ventral divided into two b}^ a deep notch. 



In the Challenger report he presents additional notes on the species 

 and gives some figures, stating that a male example 11.5 inches long 

 was still far from mature; the disk not circular, but the anterior margins 

 more rectilinear; a thin rostral appendage present; the tail showing a 

 distinct terminal fin. His figures show the ventral fin divided almost 

 into two. In this report Gunther doubtfully includes Philippics Paja 

 scobina in the S3monym3' of Psammobatis rudls. 



In the Anales del Museo Nacional de Chile, 1892, in which he rede- 

 scribes and figures Paja scobina., Philippi says of a specimen 27 cm. in 

 length, that the disk is circular; but he italicizes the statement that 

 the ventrals are situated wholl}" behind the vent, their margins rounded 

 and not divided into two lobes. We have no way of definitely decid- 

 ing whether these two forms are specificall}^ identical; but we have 

 one specimen which seems to be closely related to them, yet not fully 

 agreeing with the description of either. Inasmuch as it agrees with 

 one al)out as well as with the other and as P. scobina is the older 

 name and regarded by Gunther as probably synonymous with P. riidis., 

 we adopt it as the name for our specimen which w^e provisionally 

 identify as a Psammobatis. 



Following is a brief description of our specimen: Total length 23.5 

 inches; width 17 inches; disk with nearly rectilinear margins forward, 

 its width greater than its length, measured from tip of snout to pos- 

 terior base of pectoral fin; a short filamentous rostral projection; eye 

 8.63 in snout, 2.36 in interorbital; teeth short, bluntly conic in front, 

 nearly flat at end of jaws, -10 rows in the upper jaw and 41 in the lower; 

 ventrals not wholly behind vent, deeply notched but not divided into 

 two distinct lobes; on about the middle of the back 3 short bluntish 



