64 Bulletin 47, United States National Museum. 



87. RHINOBATUS PLAN1CEPS, Carman. 



Disk rhombic, about !-$ times as long as wide; head broad, flat ; rostral 

 cartilages moderate, dilated at tip, with the ridges close together anteri- 

 orly ; snout rounded ; spiracle with a single fold. Back and tail with 

 compressed, hooked spines ; 2 patches of spines on each shoulder and 

 a series above eye. Color brownish ; young with some white spots on 

 back. Coast of Peru and Galapagos Islands. (Garman.) (planus, flat; 

 -ceps, for caput, head.) 



Rhinobcdus planiceps, GASMAN, Bull. Mus. Comp. Zool.,168, 1880, Peru; Galapagos. 



46. ZAPTERYX, Jordan & Gilbert. 



Zapteryx, JORDAN & GILBERT, Proc. U. S. Nat. Mus., 1880, 53, (exasperala). 



This genus is close to the section Leiobatus (Syrrhina) of Rhinobatus, from 

 which it differs mainly in having the upper parts covered with coarse, irreg- 

 ular stellated prickles, instead of a uniform shagreen. The snout is of 

 moderate length and the nasal valve broader, extending on the space 

 between the nostrils. Two species known. (a-, an intensive particle; 

 Trripvt;, fin, the vertical fins being larger than in Eaja, and the ventrals 

 not emargiuate.) 



a. Disk slightly longer than broad; no yellow spots above. EXASPERATUS, 88. 



aa. Disk slightly broader than long; back with yellow spots above, surrounded with black. 



XYSTER, 89. 



88. ZAPTERYX EXASPERATES, (Jordan & Gilbert). 



Disk rhombic, rather longer than broad. Snout prominent, but bluntish 

 at tip, anterior margin of pectorals forming less than a right angle ; eyes 

 rather large ; anterior nasal valve prolonged to the internal angle of the 

 nostrils ; rostral ridges parallel, separate their whole length. Tail stout, 

 depressed, with a narrow lateral fold. Upper surface entirely covered 

 with stout, close-set, stellated prickles of different sizes, largest on the 

 bases of the pectorals and smallest on the outer edges of the fins, those on 

 the tip of snout and anterior edge of the pectorals not enlarged ; stout, 

 bluntish, slightly recurved spines present as follows : One at the upper 

 anterior angle of the eye and 2 behind it ; 1 large one at the middle of 

 the shoulders, in front of which are 2 others; 2 series on the shoulders out- 

 side the median line, the inner of 2, the outer of 2 to 4; a series of about 

 a dozen on the median line of the back and tail ; no lateral series on the 

 tail. Under side covered with shagreen, made of triangular depressible 

 asperities; region from the nostrils to the shoulder girdle smooth, except 

 the lower lip ; a few other small naked areas below. Upper lip developed. 

 Teeth i. Color brown, mottled and barred with blackish ; the markings 

 mostly in the form of transverse bands ; fore part of head blackish ; a 

 black blotch on hinder part of pectorals below. Tail rather shorter than 

 disk. First dorsal not far behind ventrals, nearer hind part of root of 

 ventrals than front of second dorsal. Snout i the length of disk, twice 

 the interorbital space. San Diego Bay; locally abundant; only male 

 specimens known. L. 2i feet, (exasperatus, made rough.) 



