DR. GtJNTHER ON THE FISHES OP CENTRAL AMERICA. 461 



176. Hekos trimaculatus. (Plate LXXVI.) 

 D. „. A. ^. L. lat. 31. L. transv. 5/14. 



Allied to //. salvini. Fold of the lower lip continuous in the middle ; scales of the 

 cheek in five series. Lower jaw prominent. Prseorbital as wide as the orbit, with the 

 antero-inferior margin concave. The length of the twelfth dorsal spine is rather less 

 than one-third of that of the head. Dark greenish olive, with three black spots ; the 

 first above the origin of the lateral line, the second in the middle of the side, and the 

 third above the end of the lateral line. Fins black. 



Three adult examples, from 8 to 11 inches long, and one of 2^ inches, were collected 

 by Mr. Salvin at Chiapam and Huamuchal. 



Description. — The height of the body is contained twice in the total length (without 

 caudal), the length of the head twice and two-thirds. Head nearly as high as long ; 

 snout rather pointed, much longer than the eye, with the cleft of the mouth very 

 oblique, and the lower jaw prominent ; the maxillary extends nearly to the vertical 

 from the front margin of the orbit. Praeorbital as wide as the orbit, with the antero- 

 inferior margin concave. The width of the orbit is one-fifth of the length of the head, 

 but only two-thirds of that of the interorbital space. The eye is situated immediately 

 below the concavity of the upper profile of the head, and is very slightly nearer to the 

 tip of the snout than to the opercular margin. Opercles scaly ; suboperculum with two 

 series of scales. The vertical fins are scaly at the base. Dorsal spines of moderate 

 strength and length, the twelfth being rather less than one-third of the length of the 

 head. The points of the soft dorsal and anal extend beyond the middle of the caudal. 

 Caudal much rounded. The distance between the caudal and the dorsal is considerably 

 less than the depth of the free portion of the tail. Pectoral much shorter than the 

 head, extending only to the second anal spine ; ventrals with the outer ray produced. 

 The distance between the vent and theroot of the ventrals is nearly half the length of 

 the head. The coloration of the young example is exactly the same as that of the adult. 



177. Herds dovii. (Plate LXXIII. fig.- 4.) 

 Giinth. Proc. Zool. Soc. 1864, p. 154. 



D. jj^. A. ^^. L. lat. 35. L. transv. "jg. 

 The fold of the lower lip is continuous in the middle. The height of the body is 

 contained thrice in the total length (without caudal) ; the length of the head twice and 

 three-fifths. Snout pointed, with the lower jaw very prominent. Prseorbital with the 

 antero-inferior margin but slightly concave, its greatest width being three-fourths of 

 that of the orbit. Both jaws with a pair of fangs, those of the upper pair being close 

 together in the middle of the jaw, whilst the lower are separate. Scales on the cheek 

 small, rather irregularly arranged, in about eight series. The first dorsal spine is 

 inserted behmd the vertical from the upper end of the gill-opening. Dorsal and anal 



