NATURAL SCIENCES OF PHILADELPHIA. 133 



Description of five New Species of the Genus UNIO. 

 BY ISAAC LEA. 



Unio Siamessis. Testa laevi, transversa, subcylindracea,ad basim emarginata, 

 valde inaequilaterali, subeompressa, ad latere planulata, postice truncata, antice 

 rotundata ; valvulis tenuissimis, diapbinis ; natibus prominulis ; epidermide 

 luteo-oliva; dentibus carditialibus acicularis, sublongis, obliquis ; lateralibus 

 loneis, laraellatis suhrectisque ; margarita alba et iridescente. 



Bab. Siam ; C. M. Wheatley. 



Unio asperulus. Testa plicata, elliptiea, inaequilaterali, postice subbiangu- 

 lata, antice rotundata; valvulis subtenuibus ; natibus subprominentibus, ad 

 apices undulatis ; epidermide viridi-oliva, obsolete ndiata ; dentibus cardinali- 

 bus laraellatis, parum obliquis, in dextro duplicibus ; lateralibus sublongis, 

 lamellatis subcurvisque ; margarita caerulea et valde iridescente. 



Hab. Siam ; Tbomas R. Ingalls, M. D. 



Unio pilatds. Testa laevi, elliptica, valde insequilaterali, postice obtuse 

 angulata, antice rotundata ; valvulis crassiusculis, antice crassioribns ; natibus 

 subprominentibus, ad apices minute undulatis; epidermide luteo viridi, 

 micanti, obsolete radiata ; dentibus cardinalibus duplicibus; lateralibus sub- 

 longis, subrectis lamellatisqne ; margarita alba et valde iridesceute. 



Hab. Siam ; Thomas R. Ingalls, M. D. 



Unio evitatcs. Testa laevi, elliptica, valde insequilaterali, postice subbiangu- 

 lata, antice rotundita; valvulis subtenuibus, antice parum crussioribus ; nati- 

 bus prominulis, ad apices divaricate undulatis; epidermide olivacea, obsolete 

 radiata ; dentibus cardinalibus parviusculis, compressis, in utroque valvulo 

 duplicibus; lateralibus sublongis, subrectis lamellatisque ; margarita alba et 

 iridescente. 



Hab. Bengal ; W. A. Haines. 



Unio Strebelii. Testa laevi, oblonga, ad latere compressa, inaequilaterali, 

 postice obtuse angulata ; antice rotundata ; valvulis subcrassis, antice aliquan'o 

 crassioribns ; natibus prominulis; epidermide luteo-fusca, radiata ; dentibus 

 cardinalibus subcrassis, elevatis, crenulatis, in utroque valvulo duplicibus; 

 lateralibus sublongis, subcrassis, subcurvatus corrugatisque ; margarita vel 

 purpurea vel salmonea et valde iridescente. 



Hab. Vera Cruz, Mexico ; G. Strebel. 



\ 



Description of two New Species of the Genus LITHASIA. 

 BY ISAAC LEA. 



Lithasia cylindrica. Testa striata, cylindrace^, flavescente, vittata vel 

 evitata ; spira subelevata ; suturis irregulariter impressis ; anfractibus coa- 

 strictis, ultimo grandi ; apertura subconstricta, rhotuboidea ; labro acuto, 

 sinuoso; columella alba et valde sinuosa. 



Hab. Coosa river; E. R. Sbowalter, M. D. 



Lithasia Wheatleyi.* Testa laevi, subc.vlindracea, luteo-virente, vittata ; 

 spira elevata ; suturis irregulariter impressis, anfractibus planulatis, ultimo 

 subgrandi ; apertura subconstricta, rhomboidea, intus vittata ; labro acuto. 

 sinuoso; columella alba et Vi.lde iride&cente. 



Hab. Cahaba river, Alabama, E. R Sbowalter, M. D. 



* Named after Mr. C. M. Wheatley, to whom I am indebted for the possession of a specimen 



1866.] 



