30 CALIFORNIA ACADEMY OF SCIENCES 



area on top of head are much wider, and the nature of the lengthwise groove is 

 widely different. 



Type, 6 , 21 cm. long. 



Head 3-| in length to base of caudal; depth 5. Greatest width of head -if its length; inter- 

 ocular width 2\; snout 3; width of mouth (at outer angles) 2^; eye 5|-; pectoral spine i|. Anal with 

 22 rays, including anterior rudiments. 



Head narrow, the occiput slightly depressed opposite the upper angle of the opercle. Snout 

 narrow, depressed, subtruncate anteriorly. Top of head with a very few minute granules, most 

 numerous on the occipital plate, where they are more or less confluent to form wavy irregular lines. 

 The occipital plate is wider than long by the diameter of the pupil; its posterior half is narrow, the 

 lateral margins being strongly concave; the median ridge is very low, disappearing behind. The 

 median line of the head is occupied by a sharply defined deep groove, which is continuous from a point 

 opposite the posterior nostrils to a point distant from the base of the occipital plate by the diameter 

 of the pupil. This cutaneous groove is much narrower than the fontanel depression which it 

 traverses, and widens or narrows independently of the latter. Its widest points are at the anterior end 

 of the groove and at the anterior end of its posterior third. There are no strongly marked striae 

 parallel with the posterior portion of the groove. In no other species of Tachysurjis known to us is 

 there a continuous groove occupying the fontanel depression. In T. fini/tii the groove may be con- 

 tinued for a short distance in front of the sculptured area, and is then interrupted in the interorbital 

 region, to reappear anteriorly as a short narrow linear depression. T. cmmclanc has also a short 

 detached anterior portion; and this is even shorter, almost round, in T. liropus. In the type of 

 T. steindachncri, the granulated area on top of head does not send forward diverging processes, the 

 line connecting the middle of the orbits being equidistant from the front of the granulated area and the 

 posterior nostrils. In the co-type, some granulations accompany \'ery narrow diverging ridges, which 

 reach the middle of the interorbital space. 



The teeth are similar to those in other species of the genus. The palatine patches are large, 

 well separated, of very coarse granular teeth. The maxillary and mandibular bands are wide, of villi- 

 form teeth except for those forming a backwardly projecting lobe near mandibular s) mphysis; these 

 being coarsely granular. 



Eye large, 2-| in interorbital witith. The maxillary barbel extends beyond pectoral 

 pore to end of basal sixth of the spine. The outer mental barbels reach to opposite base of 

 pectoral spines, the inner barbels being half their length. The pectoral pore is a narrow slit scarcely 

 half the length of nostril. The branchiostegal membrane has mesially a very narrow, free fold (not 

 to be made out in the co-type). Gill-rakers slender, 5+12, the longest half the diameter of 

 the orbit. 



The pectoral spines are short and heavy, their width at base y\- their length, which is half 

 the distance from margin of branchiostegal membrane to insertion of ventrals. The outer edge of the 

 spine is weakly serrate near tip, minutely tuberculate elsewhere; the inner margin is provided with 

 rather small, closely appressed teeth. The dorsal spine is broken in the type, f the length of 

 the head in the co-type, the dorsal rays projecting well beyond it. The base of the adipose dorsal 

 equals \ the length of the head. The sexual orifice is very slightly nearer base of inner \'entral 

 rays than front of anal. In the (male) type, the ventrals fail to reach front of anal by \ their 

 length; in the female specimen they slightly overlap it. 



Light grayish brown above, with greenish and bluish reflections; silvery below. Inner faces of 

 paired fins uniformly black in type (male), the basal half only blackish in the female. Anterior half 

 of ventrals dusky. 



