Genres des Poissons. 27 



as they pass outward, long, narrow, simple, with irregularly curved 

 apices. 



On some portions of the lingual membrane the cusp of both central 

 and latei-al teeth are much more produced than on others, the lower 

 cusp being quite spoon-shaped. 



With respect to the habits of Cylindrella and Maorocera?nus, 

 we are indebted to Mr. C. P. Gloyiie, of Jamaica, for the infor- 

 mation that they feed on lichens growing on walls and rocks — 

 lie has found their stomachs and intestinal canals filled with 

 such matter. He also remarks that the sinistral species 

 (C gracilis, etc.) appear to be viviparous, as he had frequently 

 found four or five youns^ shells, with several whorls, within living 

 adults, but that while he had never detected eggs, he had not 

 seen such embryo shells in the group to which C. sanguinea^ 

 etc., belong [Thaumasia, Cr. and Fisch.). 



III. — Genres des Poissons de la Fatme de Cuha^ appartenant 

 a la Famille Percid^, aveo une Note d^ introduction par 

 J. Carson Brevoort. 



By Felipe Poey. 



Read March 7th, 1871. 

 INTRODUCTORY NOTE. 



[The difficulty in establishing a permanent generic group of animals 

 defined by truly natural characters, is well known to naturalists, and 

 to those more especially, who, as in the case with fishes, have to study 

 preserved, and therefore shrunken and faded specimens. The want 

 of a complete series of all the spacies and varieties, taken at all 

 seasons and at all ages, and in both sexes, together with accurate 

 data concernuig their habits, geographical range, rarity of occurrence 

 and appearance when fresh, causes insuperable difficulties in properly 



