XXXV. XENATHERINA 83 



female lays thousands of eggs, where millions are laid by other forms" — 

 Thompson (/. c). 



The eggs of Leuresthes lack the long filament developed in Meni- 

 DiA and other genera, and considered as characteristic of the family. 

 This is probably a generic character, confirming the distinctness of 

 Leuresthes from Menidia. 



XXXIV. LABIDESTHES Cope, 1870. 



Labidesthes Cope, Proc. Amer. Phil. Soc, 455, 1870; Jordan and Gilbert, Bull. 

 U. S. Nat. Mus., 16, 405, 1883; Jordan and Evermann, ibid., 47, pt. 1. 805, 

 1896. 

 Orthotype. — Chirostoma sicculum Cope. 

 Range. — Fresh waters of eastern United States. 



132. Labidesthes sicculus (Cope), 1865 



St. 



Chirostoma sicculum Cope, Proc. Acad. Nat. Sci. Phila., 81, 1865. 



Labidesthes sicculus Cope, Proc. Amer. Phil. Soc, 455, 1870; Jordan and Ever- 

 mann, Bull. U. S. Nat. Mus., 47, pt. 1, 805, 1896, and of authors in general. 

 Type-locality. — Grosse Isle, Detroit River. 

 Range. — Streams, lakes and ponds from the Great Lakes Region of North America 

 southward to Texas and Florida. A most graceful little fish. 



XXXV. XENATHERINA Regan, 1908. 



Xenatherina Regan, Biol. Centr.-Amer., Pisces, 64, 1907; Jordan, Proc. U. S. 

 Nat. Mus., 309, 1919. 

 Orthotype. — Menidia lisa Meek. 

 Range. — East coast streams of southern Mexico. 



This genus differs remarkably from all others in the family in 

 squamation, the anterior part of the body being largely devoid of scales. 

 In this respect it is approached only by the unrelated and even more 

 aberrant genus Iso, of the western Pacific. The details of squamation 

 are described by us in a recent publication (Jordan, 1919). Xena- 

 therina was probably derived from a type like Thyrina, which genus 

 it resembles in several respects, such as the shortened belly, elongated 

 anal fin, the extension of the air bladder a short distance into the 

 urosome, and the slenderness of the mandibular rami. In addition to 

 its peculiar squamation, Xenatherina differs from the typical Atheri- 

 NOPSiN^E in the narrowly dilated premaxillaries, less curved and less 

 restricted gape, and more slender mandibular rami. 



133. Xenatherina lisa (Meek), 1904.-^'- 

 (Plate X, Fig. 37) 

 Menidia lisa Meek, Publ. Field Mus. (Zool), 5, 182, fig. 63, 1904 (figure poor). 

 Xenatherina lisa Regan, Biol. Centr.-Amer., Pisces, 64, 1907; Jordan, Proc. 



U. S. Nat. Mus., 309, fig. 1, 1919. 

 Type-locality. — Refugio, Vera Cruz, Mexico, in the Rio Tonto, a tributary of 

 the Rio Papaloapam. 



