cypbinodontiDjE. 617 



Eight species from the West Indies and the southern 

 parts of South America. — Allied genera are the Central 

 American Pseudoxiphophorus and Belonesox. 



Anableps. — Head broad and depressed, with the supraorbital 

 part very much raised. Body elongate, depressed anteriorly and 

 compressed posteriorly. Cleft of the mouth horizontal, of mode- 

 rate width, the mandible being short ; upper jaw protractile. 

 Both jaws armed with a band of villiform teeth, those of the 

 outer series being largest and somewhat movable. The integu- 

 ments of the eye are divided into an upper and lower portion 

 by a dark-coloured transverse band of the conjunctiva ; also the 

 pupil is completely divided into two by a pair of lobes projecting 

 from each side of the iris. Scales rather small or of moderate 

 size. Dorsal and anal fins short, the former behind the latter. 

 The anal fin of the male is modified into a thick and long scaly 

 conical organ with an orifice at its extremity. 



Three species from tropical America. They are the 

 longest Cyprinodonts, attaining to the length of nearly 

 twelve inches. Their peculiar habit of swimming with part 

 of the head out of the water has been noticed above (p. 113). 



II. Cypeinodontid.^ Limnophag^. — The hones of each 

 ramus of the mandible are hut loosely joined ; intestinal tract 

 ivith numerous circumvolutions. Sexes differentiated. Mud- 

 , eating. Tropical America. 



PoECiLiA. — Cleft of the mouth small, transverse ; mandible 

 very short. Both jaws with a narrow band of minute teeth. 

 Scales rather large. Origin of the anal fin generally nearly 

 opposite to that of the dorsal fin in the female, but in the male 

 it is modified into an intromittent organ and much advanced. 

 Dorsal fin short, with not more than eleven rays. 



Sixteen species. 



MoLLiENESiA. — Differing from Poecilia in having a larger 

 dorsal fin, with twelve or more rays. 



Five species. The males are most beautifully coloured, 

 and their dorsal fin is much enlarged. In one species (M. 



