596 I'llOCEEDINGS OF THE NATIONAL MUSEUM. VOL.XXII. 



NEPHRONAIAS YZABALENSIS Crosse and Fischer. 



* Unio yzdbalensia CROSSK and FISCHER, J. do Conch., XL, 1892, p. 294. * FISCHER 



and CROSSE, Miss. Sci., Pt.7, II, 1894, p. 597, pi. LXIV, figs. 4, 4a, 4&. 1 



Lake Ysabal, Guatemala. 



t NEPHRONAIAS RUGULOSUS Charpentier in Kuster. 



* Unio rugulosus CHARPENTIER in KUSTER, Couch. Cah. Unio, 1856, p. 154, pi. XLIV, 



fig. 5.* P.ETEL, Conch. Sam., Ill, 1890, p. 166. 2 



Habitat. A shell in the Lea collection, which I take to be this, is 

 marked " Mexico." 



NEPHRONAIAS PERSULCATUS Lea.' 



* Unio persulcatm LEA, Pr. Ac. N. Sci. Phila., XI, 1859, p. 153; * Jl. Ac. N. Sci. 



Phila., IV, 1860, p. 255, pi. XL, fig. 135 ; * Obs., VII, 1860, p. 73, pi. XL, fig. 135. 



* MUSGRAVE, Phot. Conch., 1863, pi. n, fig. 3. * B. H. WRIGHT, Check List, 

 1888.* FISCHER and CROSSE, Miss. Sci., Pt. 1, II, 1894, p. 614. 



* Margaron ( Unio) persulcatm LEA, Syn., 1870, p. 36. 



Mexico. 



f NEPHRONAIAS CALIMATARUM Morelet. 



* Unio calimatarum MORELET, Teat. Noviss., I, 1849, p. 30." ? SOWERBY, Conch. 



Icon., XVI, 1868, pi. LXXIV, fig. 385.- 1 * B. H. WRIGHT, Check List, 1888. 



* P.KTEL, Conch. Sam., Ill, 1890, p. 147. * FISCHER and CROSSE, Miss. Sci., 

 Pt. 7, II, 1894, p. 612. 



Margaron ( Unio) calimatarum LEA, Syn., 1870, p. 63. 



Mexico; Guatemala. 



t NEPHRONAIAS TABASCOENSIS Charpentier in Kuster. 



*Unio tdbascoemis CHARPENTIER in KUSTER, Conch. Cab. Unio, 1856, p. 153.pl. 



XLIV, fig. 3 5 . * B. H. WRIGHT, Check List, 1888.* CROSSE and FISCHER, 



Miss. Sci., Pt. 7, II, 1894, p. 611. 

 * Margaron ( Unio) tabascoensis LEA, Syu., 1870, p. 61. 



Mexico; Honduras; Cuba? 



1 Probably a mere variety of ceruginosus. 



2 Kuster credits this species to Australia and says that it has a purple nacre. The 

 nacre of all the Australiau species is whitish, and the shell is evidently a member of 

 this group. 



3 This and the related species are extremely puzzling. Although I have been able 

 to examine a good deal of material, yet 1 find great variation in the specimens, and 

 few of them acurately agree with the figures and descriptions. 



Fischer and Crosse believe this to be Morelet's species. It looks like a short 

 ciiprinus, but Sowerby says it is solid, and has a dirty-white nacre, while cuprinus 

 is rather thin and is copper colored throughout. 



6 The specimens which I have seen do not wholly agree with Kuster's figure and 

 description, but are nearer to that than anything else. The material in the U. S. 

 National Museum is mostly from Honduras though there are specimens credited to 

 Cuba. Lea referred these to N. scamnatus Morelet. 



