7. HEEOS. 291 



upper part of the root of the caudtil ; a narrow streak of the same 

 colour from the mouth to the angle of the praeoperculum. {Heck.) 

 Rio Negro. 



Hr. Kaup, to whom the labours of Heckel and of Miiller and 

 Troschel on the present family — nay, the family itself — are unknown, 

 describes a genus of fishes, Jloplarchus, composed of a species of If eras 

 and of one of Acnni. The former appears to bo identical with //. 

 psittaciis, Heck. With regard to the figure, it must be remarked, 

 that the greater part of the scales are lost in the tj'pical specimen, 

 and that Hr. Kaup says of the lateral hue, that it mai/ have been 

 formed by eighteen scales. 



10. Heros urophthalmus. 

 D. 1^. A. |. L. lat. 28. L. transv. 5/12. 



The fold of the lower lip is continuous in the middle. Scales on 

 the cheek in six series. Body with seven dark cross-bands ; a large 

 black ocellus on the base of the caudal fin. 



Guatemala. 



a-c. Fine specimens (seven inches long). Lake Peten. From the 

 Collection of Messrs. Salvin and Godman. 



Description. — The height of the body is contained twice and a half 

 or twice and a quarter in the total length (without caudal), the length 

 of the head nearly three times. Head as high as long ; snout rather 

 elevated, with the cleft of the mouth obhque and Avith the lower 

 jaw prominent. Teeth in nari-ow bands, those of the outer series 

 enlarged, with bro^m tips. The maxillary extends nearly to the 

 vertical from the front margin of the eye ; prasorbital as wide as the 

 orbit, the diameter of which is less than the extent of the snout, and 

 contained four times and a half in the length of the head. Inter- 

 orbital space flat, wider tlian the orbit. The eye is situated imme- 

 diately below the upper profile, nearer to the extremity of the snout 

 than to that of the operculum. Oporcles scalj-, the scales being 

 larger than those on the check ; suboperculum with two series of 

 scales. 



Dorsal and anal fins scaloless ; dorsal spines of moderate length 

 and strength, the length of the twelfth being two-fifths of that of 

 the head ; the points of the soft dorsal and anal extend to, or nearly 

 to, the middle of the caudal fin. The free portion of the tail is liigher 

 than long. Caudal rounded, its length being contained four times 

 and a third in the total. Anal spines strong and long. I'cctoral 

 rounded, extending to the third anal spine ; the outer ventral ray 

 produced. The distance between the vent and the root of the ven- 

 tral is three-fifths of the length of the head. 



Brownish- or greenish -olive, witli seven blackish cross-bands, as 

 broad as the intei-spacos between : the first descending obliquely 

 backwards, across the najie ; the second, third and fourth below the 

 spinous dorsal, the fifth hclnw the anterior, the sixth below the pos- 



V 2 



