30 CALlFOltMA ACADLMY OF SCIENCES 



area on top of licail iiro much wiilff, ;iii<I llic iKitiirc of the Iciintliwi.so <:;roovc is 

 widely (litToreiit. 



Tvpe, S , '2\ cm. long. 



Ht-ail ,vj in Icnj^'tli to base of caudal; i-lcplh 5. Greatest widlh of head if its lenj^th; intei- 

 ocular width '2\: snout 3; width of mouth (at outer anjjles) 2^; eye 5^; pectoral spine i J. Anal u ith 

 22 rays, includini; anterior ruilinicnis. 



Heaii narrow, the octiput slij;htly tiepressed opjjosite the upper anisic of the o|)erc]e. Snout 

 narrtiw, depressed, sulitrunaite anteriorly. Top of heail. with a very few niiiiute granules, most 

 numerous on the occi|)ital plate, where they are mt)re or less conlluent to form wavy irri'i^ular lines. 

 The occipital I )late is w itler than long by the diameter of the i)\ipil; its posterior half is narrow, the 

 lateral margins being strongly concave; the median ridge is very low, disapiiraiini; hcliiml. '1 In- 

 median line of the head is occupied by a sharply detlned deep groove, which is ct)ntiniious from a point 

 op]josite the posterior nostrils to a point distant from llu' base of the occipital plate by the diameter 

 of the pupil. This cutaneous groove is much n.nrciuir tlian tin- fontam-l dcpiession which it 

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

 of the groove ami at the anterior end of its ]X)sterior third. There are no strongly marked stria- 

 parallel with the posterior portion of the groove. In no other s|)ecies of Tachystirus known t<> us is 

 there a continuous groove occupying the fontanel de])ression. In 7". y//;///// 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 dejjrtssion. T. ct)n>icla)>c has also a short 

 detached anterior portion; and this is even shorter, almost round, in T. liropus. In the tyjx' of 

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

 line connecting the middle of the orbits being ccpiidi.stant 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 s|)ace. 



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

 well sejiarated, of very coarse granular teeth. The ma.xillary and mandibular baiuls are wide, of villi- 

 form teeth except for those forming a backwardly projecting lobe near mandibular symphysis; these 

 being coarsely granular. 



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

 jx>re 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 ])ore 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 yV '^'''^''' le".!^t'i. "liich is half 

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

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

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

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

 equals \ the length of the head. The sexual orifice is very slightly nearer base of inmr ventral 

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

 length; in the female sjiecimen 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. 



