2 THK NAUTILI'S. 



seen in the United States Collection of the American Association of 

 Conchologists, in the Academy of Natural Sciences of Philadelphia. 



TJnio Pleasii. 



Shell smootli, oval, sliglitly elliptical, very inequilateral, valves 

 rather thin, somewhat compressed, regularly rounded before, obtusely 

 angular behind, beaks very small and tiat, undulations very minute. 

 Ej)idermis greenish-olive, usually covered with green capillary rays 

 posteriorly, sometimes rayless. Cardinal teeth small, erect, cren- 

 ulate, single in the right, and double in the left valve, sometimes 

 tripartite in left valve ; lateral teeth short and slightly curved, an- 

 terior cicatrices deeply impressed, posterior cicatrices very slightly 

 impressed, confluent ; nacre varying from pale rose to pale salmon, 

 often silvery white and iridescent. 



Habitat. Little Red River, Arkansas. 



Remarks. In general form this shell bears some resemblance to 

 Unio spatulatns Lea, but differs from that shell in being a much 

 smaller and thinner shell, very much more compressed ; its cardinal 

 teeth are entirely different ; it is not spatulate in form, and is very 

 much more inequilateral ; tlie nacre ditfers entirely ; the very peculiar 

 character of the females of this species must distinguish it from all 

 others ; they are deeply emarginate, very oblique, and sharp pointed 

 posteriorly, bearing some resemblance to the females of Unio 

 conradianus Lea. 



I name this shell after my friend, Mr. Ellwood Pleas, of Indiana, 

 who collected this species, with many other rare shells, in the interior 

 of Arkansas. Typical specimens of both male and female are in the 

 American Association Collection in Philadelphia. 



EDIBLE MOLLUSKS. ETC., HEKE AND THERE. 



Mr. Carpenter's article in the last number of The Nautilus, is 

 fully as entertaining and profitable as his previous communications. 

 It may be his last is a trifle more thrilling, and when this is supple- 

 mented by the usual spice of discrepancy, the picturesqueness 

 is enhanced and the thoughtful reader is for awhile diverted from 

 the plodding habit of careful definition and rational interpretation, 

 and led unconsciously to soar far and wide on the reckless wings of 

 fancy, and revel free and easy, in the salubrious atmosphere of 

 fiction. The author's loyalty to Rhode Island is certainly commend- 



