124 [July, 



from the dorsal groove; from this, tlie height of the fin decreases regularly to 

 its end, the last ray being about inch high ; 1st three rays of anal spinous, 

 the outline of the fin being somewhat scolloped; about 68 scales along the 

 lateral line; about 28 narrow silver longitudinal bands, mucous ducts irregularly 

 dispersed over the head ; head brown and transparent gray ; back, lead color 

 above the lateral line ; edge of the dorsal membrane black ; scales along the base 

 of the fins smaller than elsewhere, those along the anterior portion of the anal 

 very small. 



Entire length 14 inches ; in width, , weight 2 to 3 lbs. 



D. 35; P. 26 ; V. 6; D. 32; C. 20. 



C. elmptictts, Gibbons. Similar in general characters to the Lar&insit, 

 body compressed, lighter and more silvery lustre, transverse bands darker, with 

 a line of dark spots along the dorsal ; edge of anal tipped with black. Extreme 

 length 9 inches, width 4 inches, weight i pound. 



Hysterocarpus, Gibbons. 

 Head of medium size ; snout protractile, lips moderately thick; body ovate, 

 compressed, arched ; cheek and opercle covered with scales, membranous round 

 the edges; teeth conical, in a single row, not extending along the sides of the 

 jaws. Branchiostegal rays 5. Pectoral opposite the dorsal. Intestinal canal 

 short, with two inflexions enlarged at each extremity. Scales large, deciduous. 

 Lateral line nearly concurrent with the back. 



H. Traskii. Radius of curvature least along the anterior half of the dorsum. 

 Facial line about 45 degrees; profile slightly incurved along the interparietal 

 and frontal bones. Lower jaw the longer. Eyes rather large and near the 

 facial outline. The dorsal has 17 strong, curved spines: 1st short, the succeed- 

 ing ones increasing regularly in length to the 6th, which is the longest. The 

 spinous rays lie in a groove, but only the two first are hidden by it, the others 

 project about quarter of an inch above it, and alternately lap by each other so as 

 to form a double row. 



Pectoral subquadrangular, with the lower edge rounded, and the first ray short 

 and subspinous. First ray of the ventrals shorter than the others, spinous and 

 curved. First three rays of the anal spinous, short, thick and curved, the middle 

 one largest. 



Scales smaller on the summit of the back, on the opercula, at the base of the 

 tail, of the anal and ventrals, and on the space bounded anteriorly by the ven- 

 trals and pectorals. 



Color. Back varies from ash color to dark brown ; irregular blackish patches 

 approximating somewhat to bands across the sides. Belly lemon yellow, be- 

 coming lighter and blending with the ash color up the sides. Sides in some, 

 punctated with black, dark and yellow patches on the fins. Extreme length 

 G,5 inches, width 3 inches, weight 2 ounces. 



D. 28 ; P. 18 ; V. 6 ; A. 23 ; C. 22. 



Var. A. Facial line not so angular as the other, head deeper, less dorsal cur- 

 vature, and no black bands. 



The anatomy of these is similar to that of the viviparous species which I have 

 already described, except that the uterus, instead of being bipartite at its anterior 

 extermity, is ovoid, and has but a single system of uterine blood vessels. 



The specimens from which this description is made were presented to me by 

 my friend, Dr. J. B. Trask, who obtained them through the kindness of Mr. 

 Morris, from the fresh water lagoons of the Sacramento river, and from the 

 river, where they are found as high up as the fishermen have yet been. 



Hyperprosopon, Gibbons. 



Head of medium size ; body compressed, oval ; snout protractile; lips thin ; 

 cheeks, opercle and preopercle scaly, with membranous edges ; teeth conical, 

 in a single row, extending all round the lower jaw, and about half way down 

 the upper one; branchiostegal rays 6; dorsal commences behind the pectorals 



