288 CU ROM IDES. 



fleshy hump on the ii;q)o of the neck, which is probably a character 

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

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

 Pra?orbital much wider than the orbit, the diameter of which is one- 

 half of tlio length of the snout. Cleft of th(^ mouth slightly oblique, 

 with the lower jaw a little prominent l^eyond the upper ; the max- 

 illary is liidden l)el(;w the ])ra;orbital, and does not extend to the 

 front margin of the eye. Jaws protractile, armed with a broadish 

 band of vUiform 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 lins have a few small scales at the 

 base. Dorsal spines of moderate strength and lengtli, the length 

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

 Tlie soft dorsal and anal arc somewhat elevated in th(> 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 s])ine. The outer ventral ray is produced 

 into a short filament. 



Ih'ownish-olive, with seven black cross-bands : tlie first in front of 

 the dorsal fin ; the second to the fifth below the spinous doi'sal, partly 

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

 seventli across the free ])ortion of the tail. Each of these cross- 

 bands has numerous pearl-coh)ured spots. Root of the caudnl witli 

 a blackish spot. 



5. Heros melanurus. 



D. if A. |. L. lat. '63. L. traiisv. f, i;}. 



The fold of the lower lij:) is subinterrupted in tlie middle* ; five 

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

 twice and a third or twice and a half in the total lengtli (witb<nil 

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

 parts black iu adult specimens. 



(juatemala. 



(i-e. From three lo ten inches long. Lake Pcten. From the (!ol- 

 lecticjii of Messrs. Godman and Salviu. 



Discri/'tion. — Head higher than long, its length being nearly one- 

 tliird 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- 

 tliird of tliat of the head. I'nooi'bital wider than the orbit. Cleft of 

 the mouth oblique, with the lower jaw scarcely prominent. 'J'lie 

 maxillary does not extend to the vertical fi'om tlie front margin of 

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

 teeth, those of the outer series being the larger and l)rown at the 



* The fold is distinctly interrupted in i^]ieeimens from six to ten inelies lonp;, 

 whilst it apjieai's to be slightly continuous in young individuals of three to four 



iiu'hes in Icniflh. 



