40 NEW UMON'ID.i; OF THE 



slightly impressed ; dorsal cicatrices placed on the under side of the cardinal tooth ; 

 cavity of the shell wide and shallow ; cavity of the beaks rather deep and angular ; 

 nacre silver white and somewhat iridescent. 



Soft parts. — Branchial uterus was not charged, but ova were in the ovarium. Branchvv. 

 large, very thin, semicircular, inner one very much the larger, free nearly two-thirds 

 the length of abdominal sack. Palpi large, thin, subtriangular, united half way 

 down the posterior edges. Mantle very thin, thickened on the edges. Branchial 

 opening rather large, with numerous small brownish papilla;. Anal opening rather 

 small, with smooth edges, devoid of all appearance of papillaj. Super-anal opening 

 very large, colored on the inner edges and united below. Anm very small ; color of 

 the mass dirty white. 



Remarks. — I received from Prof. Forshey two perfect specimens, one with the soft 

 parts and several old valves. The one figured is not full grown. It is a very 

 beautiful and interesting species, and very nearly allied to lacrymosus (nol)is). It 

 differs in" having small tubercles, and these are pretty regularly distributed over the 

 whole disk. It is also much more compressed, and the tubercles on -the anterior and 

 posterior slopes are more numerous and more regularly placed in rows. In this respect 

 I have seen no Vnio so ornate. It also has a close resemblance to a half grown U. 

 Blandianns (nobis), but is more compressed and has more and smaller tubercles. 

 The interior is remarkably white, and the surface of the nacre down the medial 

 portion is beautifully waved by the tubercles on the exterior. 



The specimen from Mr. Anthony is higher on the umbonial slope, where it is more 

 coiTugate and the. posterior slope also is higher. 



I dedicate this species to Prof. Forshey, who has done much to elucidate the 

 Natural History of the Southern States. 



Unio Houstonensis. pi. 60, fig. 183. 



Testii laevi, subrotunda, subinflata, {equilateral!, ad latere paulispcr planulata ; valvuli.s subcrassis, antiee 



crassioribus ; natibus elevatis, ad apices paulisper undulatis ; epidermide lasvi, luteo-fusca, vel eradiata 



vcl obsolete, radiata ; dentibus cardinalibus inagnis, erectis, crenulatis ; lateralibus curtis subrectisquc; 



margaritS, argentea et iridesoente. 



Shell smooth, nearly round, somewhat inflated, equilateral, a little flattened on the 



side; valves rather thick, thicker before ; beaks raised, slightly undulate at the tips; 



epidermis smooth, yellowish brown without rays or obscurely rayed; cardinal teeth 



large, erect and crenulate ; lateral teeth short and straight ; nacre silvery white and 



iridescent. 



PiPC. Acad. Nat. Sol. l.S5!.», p. 150. 



Hab. — Houston, F. Moore, M. D. ; and Rutersville, Texas, Prof. Forshey. 

 My cabinet and cabinets of Dr. Moore and Prof. Forshey. 

 Diani. Tl. Length 1-3. Breadth V-S inch. 



