7. HERos. 297 



root of the caudal. A black spot above the origin of the . lateral 

 band. Opercles, back, and vertical fins with black dots. 

 Guatemala. 



a-b. Seven inches long. River of Cahabon. From the Collection of 

 Messrs. Godman and Salvin. 



Description. — The length of the head is contained thrice or thrice 

 and a third in the total (vsdthout caudal). The profile of the nape is 

 much curved. Head as high as long; snout rather elevated, the 

 prseorbital being wider than the orbit. Cleft of the mouth rather 

 narrow, horizontal, Avith the jaws equal anteriorly, and with the 

 maxillary not extending backwards to the vertical from the front 

 margin of the eye. The six front teeth of the outer series are the 

 longest, deep-brown. The nape is elevated, and the orbit consider- 

 ably below the upper profile of the head. Opercles scaly. 



Dorsal and anal fins very slightly scaly at the base ; the spinous 

 dorsal is low, the length of the twelfth spine being one-fourth of that 

 of the head ; the soft dorsal and anal are somewhat produced, extend- 

 ing beyond the root of the caudal. The free portion of the tail is 

 somewhat higher than long. Caudal subtruncated, one-fifth of the 

 total length. Pectoral shorter than the head, but rather longer than 

 the ventral, which does not extend to the vent. 



22. Heros nebulifer. 

 Chromis nebiilifera, Gilnth. Proc. Zool. Soc. 1860, p. 318. 

 D. J|. A. |. L. lat. 35. L. transv. 6/13. 



The fold of the lower lip is interrupted in the middle ; six series 

 of scales on the cheek. The height of the body is contained twice 

 and two-thirds in the total length (without caudal). Nearly uniform 

 greenish-oHve, with a black spot at the root of the caudal. 



Mexico. 



a-c. Types of the species. From M. Salle's Collection. 



Description. — The height of the body is contained twice and two- 

 thirds in the total length (without caudal), the length of the head 

 four times. The profile of the nape much curved. Head as high 

 as long ; snout slightly elevated, the prteorbital being wider than the 

 orbit. Cleft of the mouth small, horizontal, Avith the jaws equal 

 anteriorly ; interorbital space convex, its width being equal to one 

 and a half diameter of the eye ; opercles scaly. 



Dorsal and anal fins very slightly scaly at the base ; the spines of 

 the former of moderate strength, the length of the twelfth being 

 somewhat less than one-half of that of the head. The soft dorsal 

 and anal are not produced, and the former does not extend to the 

 root of the caudal. Caudal truncated. The free portion of the tail 

 is longer than high. Pectoral shorter than the head ; ventral not 

 prolonged. 



Greenish-olive : the middle of the body clouded with blackish, in 



