2. AGONORTOMA. 463 



the maxillary extending to below the anterior margin of the eye ; 

 it is not entirely hidden when the mouth is closed, but a narrow 

 stiip of its cutaneous covering remains visible. The pra^orbital 

 reaches downwards to the lower level of the orbit, and is not denti- 

 culated. There are nineteen scales between the spinous dorsal and 

 the crown of the head ; those on the crown are covered with skin, 

 and the interorbital space is entirely naked. The spinous dorsal fin 

 commences midway between the snout and the base of the caudal fin, 

 above the tenth scale of the lateral line ; its anterior spines are stout, 

 their length being a little less than one-half of that of the head. 

 The soft dorsal is a little higher than the spinous, not scaly, and 

 commences above the twenty-fourth scale, or above the fourth soft 

 anal ray. Caudal emarginate. The anal fin is somewhat higher 

 than the dorsal opposite, and has its anterior spine very short. The 

 pectoral is inserted on the middle of the depth of the body, and is as 

 long as the head, the length of the snout not included ; it extends 

 to the ninth scale. 



Back greyish-green, each scale with a brown margin ; a silvery 

 band from above the pectoral to the base of the caudal ; lower parts 

 silvery. 



6. Agonostoma nasutum. 

 D. 4 I -i-. A. |. L. lat. 42. L. transv. 12. 



Eather narrow bands of villiform teeth in the jaws, on the vomer 

 and palatine bones. The height of the body equals the length of 

 the head, and is one-fifth of the total. Upper lip thick. The max- 

 illary extends to the vertical from the anterior margin of the eye. The 

 interorbital space is convex. The anterior dorsal commences nearer 

 to the end of the snout than to the base of the caudal fin. 



llivers of Guatemala. 



a. Eight and a half inches long. Eiver of San Geronimo. From 

 Mr. Owen's Collection. 



Description of the specimen. — The body is moderately compressed, 

 rather thick behind the head, its greatest depth being equal to the 

 length of the head, and one-fifth of the total; its upper anterior profile 

 is slightly convex above the opercles. The interorbital space is convex, 

 and its vridth is contained twice and two-thirds in the length of the 

 head. The snout is obtusely conical, the diameter of the eye Ijeing 

 two-tliirds of its extent, or one-fifth of the length of the entire head. 

 The upper lip is thick, especially its front part, which extends to the 

 upper siu'face of the head and projects beyond the lower jaw. The 

 cleft of the mouth is slightly oblique, of moderate width, the 

 maxillary extending to below the anterior margin of the eye ; the 

 maxillary is entirely hidden when the mouth is closed. Prajorbital 

 without denticulation. Narrow bands of villiform teeth in the jaws, 

 on the vomer and on the palatine bones. There are nineteen scales 

 between the spinous dorsal and the snout, the scales extending to 

 the level of the anterior margin of the orbits. The spinous dorsal 

 commences nearer to the end of the snout than to the base of the 



