1903.] NATURAL SCIENCES OF PHILADELPHIA. 531 



subpyramidal, the mouth small, the lower jaw projecting, its tip on a 

 level with the upper margin of the pupil when it is closed ; outer teeth 

 enlarged. Eye greater than snout, 3^ in head, 1^ in interorbital. Pre- 

 orbital | the diameter of the eye. Dorsal placed far back, its origin 

 slightly in advance of that of the anal, its distance from the eye twice 

 its distance from the middle caudal ray. The last rays of the dorsal 

 and anal reaching caudal. Height of dorsal and anal equal to the 

 postorbital part of the head. Caudal rounded, about equal to the head 

 in length. Ventrals small, reaching past anus but not to anal; pec- 

 torals not quite reaching ventrals, equal to head less one-half snout. 



Dark brown, four light bands on the posterior half of the body, most 

 marked between the dorsal and anal ; ventral surface and region along 

 either side of anal colorless. Dorsal and anal fins with about four 

 longitudinal dark bands alternating with light. Caudal with numerous 

 irregular cross-bars of alternating light and dark. Ventrals and pec- 

 torals more faintly and irregularly barred. 



The single specimen is a female wdth ripe eggs. With the present 

 material it is impossible to determine whether the species is viviparous 

 or not. The generic position of the specimen is therefore in doubt. 



98. Tylosurus amazonicus (Steind.). Pez de espada. 

 One specimen (32), Laguna Asuncion. 



99. Plagioscion ternetzi Boulenger. Corubiua. 



Two specimens (41), Asuncion, Rio Paraguay. 



This species is rare, but one of the finest food fishes. The specimens 

 differ from Boulenger's type in having conspicuous black axillary spots. 



100. Pachyurus bonariensis Steindachner. Corubina. 



Three specimens (1, 144, 201), Laguna of Rio Paraguay at Asuncion; 

 Laguna of Arroyo Trementina, 



Analysis of the Genera and Subgenera of American Cichlim:: 



[a. Spinous and soft portions of the dorsal of equal extent, or the 



former the longer. 

 h. First gill-arch normal (without additional lobe above). 



c. Gill-rakers long. 



d. Gill-rakers close set and very long, setiform, numerous (about 85). 



e. Anal spines 3, alternating. Body compressed, oblong, covered with 



scales of moderate size. Dorsal spines numerous (13 or 14). 

 Each jaw with a front series of small awl-shaped teeth, behind 

 which is one or more series of smaller teeth. Cleft of mouth 

 of moderate width. Scales on cheeks in 5 or more series. Soft 

 dorsal and anal naked, 1. Ch/Etobranchus. 



