PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 33 



large ; candal fin well developed ; under side of tail flattened with a 

 blunt medial ridge. 



Under side covered with a fine shagreen, like the skin of a shark, the 

 roughnesses being triangular and closely set, depressible backwards ; 

 the skin below much as in Bhinohatiis, but the prickles higher and 

 sharper, the skin much rougher than in the latter genus. 



The branchial region, from the nostrils to the pelvic bones, is entirely 

 smooth, except the lower lip, which has a band of close-set prickles. 

 A small tract in the middle of the pelvic area is pricklj', and most of 

 the abdomen proper, back to a point in front of the vent ; the anterior 

 and outer three-fourths of the pectorals below and about half the ven- 

 trals anteriorly and exteriorly also rough, as is the whole snout below, 

 in front of the nostrils ; whole lower surface of the tail and the surface 

 of the fins rough with shagreen. 



Above, the entire surface is covered with close-set stellated prickles 

 of different sizes, largest on the base of the pectorals, and smallest about 

 the eyes and on the outer edges of the fins. 



Besides these are several stout, bluntish, slightly recurved spines, 

 with stellate bases, placed as follows : One at the upper anterior angle 

 of the eye and two behind it, the posterior the larger ; a large spine on 

 the back at the shoulder-girdle, in front of which are two or three on 

 the median line, and a series on the middle line of the back of 10 to 12 ; 

 two more on the tail between the dorsal fins ; two series on the shoulder- 

 girdle, the inner of two, the outer of two to four. 'No other large spines 

 on the body, ^o claw-like spines are present on the pectorals in the 

 male examples seen, all of which are, however, immature. 



Measurements. 



Total length 8. 4 inches. 



Length of disk, to root of ventral 4.4 inches = .51 of totall 



Breadth of disk 51 " 



Length of tail 49 " 



Snout to scapular spine 295 " 



Eye 05 " 



Snout 11 "• 



Interorhital space 055 " 



Scapular spine to first dorsal 31 '•■ 



Length of first dorsal 045 " 



Height of first dorsal 095 "■ 



Distance between dorsals 075 " 



Length of caudal fin below 15 " 



"Width between nostrils 12 " 



Width of mouth 095 " 



Snont to vent 46 "■ 



Width of branchial area 225 " 



Length of branchial area .085 " 



This species is very abundant in the Bay of San Diego, where about 

 twenty examples of both sexes, all very similar in size, were obtained.. 



This species of the Asiatic genus Platyrh'ma in the Avaters of the' 

 United States is a very interesting addition to our fauna. 



Proc. Kat. Mus. 80 3 May 6, 188©. 



