I'lxTSSION OF SPECIES AND THE1K DlSTMliUTION. 



445 



greatest lieighl over the pectorals, Hie contours then descending in almost straight lines to 

 the base of the tail. The' thickness of the body (6) is less than in ft aretifrons, being con- 

 tained Dearly 17 times in the standard length. 



The scales are thin, deciduous, smaller than in ft aretifrons. There arc about in 



scales in the lateral line, which is slightly curved over the pectoral, and, as nearly as can 



he determined in the denuded specimens before me, about 12 rows above and 12 below the 

 lateral line at the broadest pail of the body. 



The length of the bead (25) is one-fourth of the standard length and about 3 times 



the diameter of the eye i!)), or the distance from the snout to the upper eye (9). The inter 

 orbital space is w ide | 1 1, equal to the length of the snout, and diagonally crossed by a strong 

 ridge, a continuation of two ridges which form the upper boundary of t he lower and the 

 lower boundary of the upper orbit. 



The length of the maxillary (11) is less than half, that of the inaudible (13) more than 

 half, that of the head. The teeth are minute, in single rows, closely set in the jaws, some- 

 what stronger upon the blind side. A strong short spine above the snout, at the anterior 

 termination of the ridge at the' lower margin of the upper eye. Hence the specific name 

 unicornis. 



The dorsal fin begins at the side of the preorbital spine, its anterior rays being slightly 

 crowded over upon the blind side. It is composed of 73 to 75 simple rays. Its greatest 

 height (13) is half the length of the head. 



The distance of the anal from the snout (33) is one third of the standard length. The 

 number of rays is (ill; their longest (13) equal in length to the longest dorsal rays. 



The caudal is pointed, triangular, subsessile; its length (22) twice that of the maxillary 

 (11) and two thirds the distance from the snout to the anal (.'>•'!). The pectorals are inserted 

 far below the lateral line. The pectoral of the colored side is twice as long (18) as the 

 diameter of tin' eye, that of the blind .side as long (13) as the longest dorsal rays. The for- 

 mer is composed of 10 rays, the latter of 4. 



The length of the ventrals (11) is half that of the caudal. They are asymmetrically 

 placed, as is described under the generic diagnosis. 



Radial formula: D. 73-75; A. 60; 1*. 4, right, 10, left; L. hit. 40. 



Color, ashy gray, with dark lateral line. Byes black. 



( torrent number <■( specimens 

 Locality ... 



26,003 

 870 and 871. 



Milli 

 meters. 



Extreme length 



Length t iginol niitlul.-r.nHl.il rays.. 



l;..il\ 



Greatest height 



Least height of tail 



Head: 



Greatest length ■ 



DistaiK-i' !i > l to uj.|.. i . . 



Distance from snout to low >-i < \ e 



Width of interorbital area. 



Length of si t 



Lengt ii "i max illary 



Length of mandible 



Diameter of orbit, longitudinal 



Dntsal :s}»iinMi>i 



Distance from snout 



Greatest height 



A, Ml. 



Distance from snout 



Height at longest ray 



Caudal: i,«'hl*i Ii of middle rays 



Pectoral: 



Distance from snout 



Length 



Ventral : 



Distance from snout on colored side. 



Length 



Dorsal 



Anal 



Pectoral 



Number of scales in lateral line 



100tll8Of 



I - Dgth 



47 

 11 



25 

 9 

 f. 

 4 

 4 

 II 

 13 

 9 



5 

 13 



:i3 

 13 

 22 



28 

 18-13 



Jii 

 11 

 , , 

 i,ii 



I i: , in I. 

 40 



