288 CHROMIDES. 



fleshy hump on the nape of the neck, which is prohably a character 

 of mature age. Snout compressed, rather high, of moderate extent, 

 its length being contained twice and a fourth in that of the head. 

 Prajorbital much wider than the orbit, the diameter of which is one- 

 half of the length of the snout. Cleft of the mouth slightly oblique, 

 with the lower jaw a little prominent beyond the upper ; the max- 

 iUary is hidden below the prteorbital, and does not extend to the 

 fi-ont mai'gin of the eye. Jaws protractile, armed with a broadish 

 band of villiforra teeth, those of the outer series being the larger. 

 Eye nearer to the extremity of the operculum than to that of the snout. 

 Scales on the cheek not much smaller than those on the opercles. 



The soft portions of the vertical fins have a few small scales at the 

 base. Dorsal spines of moderate strength and length, the leng'th 

 of the twelfth being contained twice and a third in that of the head. 

 The soft dorsal and anal are somewhat elevated in the middle, ex- 

 tending to the base of the caudal. The free portion of the tail is as 

 long as high. Caudal fin slightly emarginate, with the lobes rounded, 

 one-fifth of the total length. Pectoral shorter than the head, ex- 

 tending to the thii'd anal spine. The outer ventral ray is produced 

 into a short filament. 



Brownish-olive, with seven black cross-bands : the first in front of 

 the dorsal fin ; the second to the fifth below the spinous dorsal, partly 

 extending on the fin ; the sixth below the end of the dorsal ; the 

 seventh across the free portion of the tail. Each of these cross- 

 bands has numerous pearl-coloured spots. Root of the caudal with 

 a blackish spot. 



5. Her OS melanurus. 



D. If. A. |. L. lat. 33. L. transv. 5/13. 



The fold of the lower lip is subinterrupted in the middle* ; five 

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

 twice and a third or twice and a half in the total length (without 

 caudal). A deep-black band along the middle of the tail ; the lower 

 parts black in adult specimens. 



Guatemala. 



a-e. From three to ten inches long. Lake Peten. From the. Col- 

 lection of Messrs. Godman and Salvin. 



Description. — Head higher than long, its length being nearly one- 

 third of the total (without caudal). There is a fleshy hump on the 

 nape of the neck of the two largest specimens. Snout compressed, 

 rather high, of moderate extent, its length being two-fifths or one- 

 third of that of the head. Pra3orbital wider than the orbit. Cleft of 

 the mouth oblique, Avith the lower jaw scarcely prominent. The 

 maxillary does not extend to the vertical from the front margin of 

 the eye. Jaws protractile, armed with a broad band of villiform 

 teeth, those of the outer series being the larger and brown at the 



* The fold is distinctly interrupted in specimens from six to ten inchei? long, 

 whilst it appears to be slightly continuous in young individuals of three to four 

 inches in length. 



