GILBERT AND STAKES — FISHES OF PANAMA BAY 155 



285. Xesurus hopkinsi sp. nov. 



Plate XXV, Fig. 48. 



Two large specimens, 41 and 43 cm. in length, were taken at Panama, and 

 cannot be referred to any of the described species. For comparison we have speci- 

 mens of X. 2>unGtatus from Mazatlan, Clarion Island, and San Benedicto Island; 

 X. laticlavius from the Galapagos Islands; and the type of X. clarionis from Clarion 

 Island. We have not sufficient material to decide upon the validity of the last-named 

 species, and for present purposes will consider it distinct from the others. 



The outlines of the body are evenly curved. The snout projects but slightly as compared 

 with the other species, and the upper anterior outline is shallowly concave. From before eye to dorsal, 

 the profile is regularly rounded and without a projection at nape. 



Dorsal VIII, 26 or 27; anal III, 23. The head is smaller than in the other species, 26 or 27 

 hundredths of the length. In seven specimens of X. punctatus, the head averages 31 1 hundredths 

 of the length; in three specimens of laticlavius, 31^ hundredths; in clarionis, 30 hundredths. The 

 mouth is smaller; the maxillary forms but 6^ hundredths of the length (in punctatus, ji hun- 

 dredths; in laticlavius, 8| hundredths; in clarionis, 8 hundredths). The teeth are much smaller, 

 though they number the same as in the other species, 8 or g on each side of the upper jaw. The eye 

 is smaller, 4 or 4^ in the snout, 5 hundredths of the length (in punctatus b^ hundredths; in lati- 

 claviiis, 7|- hundredths; in clarionis, 6J- hundredths). 



The pectoral is broad and rounded at its tip, reaching to above the base of the second anal 

 spine, when forced into a horizontal position. It seems to incline obliquely upward in its normal 

 position. The ventrals nearly reach the first anal spine, and are about two-thirds the length of the 

 pectorals. The dorsal and anal are as in related species. In the larger specimen, the first dorsal spine 

 has become almost entirely concealed beneath the skin, the first anal spine wholly concealed. 



The posterior part of the body is rather thickly covered with sharp spines, the bases of which 

 are expanded as rough plates. The spines are somewhat inclined forward and are occasionally bifid 

 (some specimens of other species have scattered rough plates which sometimes bear low sharp keels, 

 but never high spines). The three bony shields on the caudal peduncle bear thick blunt spines, their 

 points broad and smooth, as though worn. 



Color light slaty on lower parts, dark above. One specimen is faintly spotted with black on 

 nape and opercles. 



