OVERIAN STRUCTURES OF VIVIPAROUS BLIND FISHES. 39 



II. SYSTEMATIC POSITION OF LUCIFUGA AND STYGICOLA. 



Poey 1 ('60) described these fishes in 1860, giving them the 

 generic name of Lucifuga, recognizing them, however, as two 

 species, dentatus and subterraneus. Later Gill, '63. separated 

 dentatits from the other and created the genus Stygicola fortit. 

 The two genera are different in that Stygicola has teeth on the 

 palatines, where Liicifitga has none, and the teeth in the jaws of 

 the former are larger than those of the latter. There is also a 

 very noticeable difference in the depth of the head at the nape, in 

 adult individuals. The two species or genera are however so 

 nearly alike that it is only after a prolonged comparison that the 

 above technical differences were made out. 



The several species of blind cave fishes, found in Indiana, Illi- 

 nois, Kentucky and Missouri, are not related to the Cuban 

 species. The latter are descended from marine forms which have 

 worked their way through underground channels into the Cuban 

 caves. Related genera that still live in the ocean about Cuba 

 are Brotula 2 and Ogilbia? in moderate depths and Bassosetus* 

 and Apkyonus 5 in deep water. 



All of these genera belong to the family Brotulidae, a deep-sea 

 group comprising about forty-five genera and one hundred 

 species, living mostly in the tropical seas of both hemispheres. 

 The two genera under consideration in this paper are the only 

 ones found in fresh water. Jordan and Evermann (op. cit., Pt. 

 III., p. 2498) observe very properly that " these fishes are closely 

 related to the Zoarcidae. In spite of various external resem- 

 blances to the Gadidae their affinities are rather with the blen- 

 nioid forms than with the latter." 



III. HISTORICAL. 



Numerous contributions to our knowledge of viviparity in 

 fishes have been made from the time of Cuvier to the present. 



1 Lucifuga, Poey, " Memorias," II., 95, 1860 (su&ferraneas) ; Lucifuga subter- 

 rannts, Poey, "Memorias," II., 96, 1860; Luiijuga dentatus, Poey, "Memorias," 

 II., 102, 1860; Stygicola dcntata, Gill, Proc. Ac. Nat. Sci. Phil., 252, 1863. 



2 Brotula (vid. Bull. 47, U. S. Nat. Mus. , Jordan & Evermann, "fishes of 

 North America," Pt. III., p. 2500). 



3 Ogilbia {vid. idem, Pt. III., pp. 2502, 2503). 



4 Bassozetns, Gill (viJ. idem, Pt. III., p. 2507). 



5 Aphyoniis, Giinther (yiJ. idem, Pt. III., p. 2525). 



