90 LAND AND FRESII-WATER SHELLS OF N. A. [dART II. 



times, yet they are as brisk as when first taken ; and moreover they have 

 grown at least one-quarter. Exuviie white, abundant, vermicular. 



Cabinets of Boston Society of Natural History, Amherst and Middlebury 

 Colleges, Mons. Largillier, S. S. Haldeman, J. W. Mighels, and C. B. Adams. 



Hub. Monmouth, Maine : discovered in a mill-pond, after the water was 

 drawn off, by Mr. N. T. True, to whom we are indebted for specimens. 



This species is distinguished from P. heterostroplta by the campanulate 

 aperture, which is constant, shorter spire, tumid labium, and by its re- 

 markable tenuity. (^Mighels.) 



Physa fragilis, Mighels, Proc. Bost. S. N. S. I, 49 (1841). —Mighels & 

 Adams, Bost. J. N. H. IV, 44, pi. iv, f. 12 (1842).— Haldeman, Mon. 

 p. 31, pi. iv, f. 11-13 (1843).— DeKay, prelim. Cat. N. Y. Moll. 

 anno 1839, p. 32 ? * 



Dr. Foreman catalogues FJi. fragilis from the District of 

 Columbia. 



I have seen no authentic specimen of this species, which is 

 admitted by Haldeman as distinct. I am inclined to believe it a 

 variety of Ph. hetero8tropha. The original description and 

 figure are copied above. 



Pliysa seniiplicata, Kustek. — Shell ovate, shining, semi-trans- 

 parent, horn-colored ; whirls five, convex, regularly wrinkled or grooved, 

 the last smooth below ; aperture broad ; columella 

 Fig. 154. concave, sub-plicate ; peristome straight, acute. 



A species readily recognized by its peculiar sculp- 

 turing ; the shell, is longitudinally-ovate, shining, 

 transparent, horn-colqred ; the apex is somewhat 

 depressed, obtusely ovate, whirls arched, separated 

 by a depressed, transversely wrinkled suture ; body 

 whirl large, ventricose, rapidly decreasing towards the 

 rounded base, with delicate incremental striae and 

 longitudinally grooved on its upper half; mouth 

 Fhysa semiiMcata. moderately high, and especially towards the base, 

 broad; outer lip thin, straight, acute, curving and 

 obtusely rounding below ; columella short, concave, folded ; fold broad, 

 rather thin, white. Height 5, breadth 3'". 



Ilah. Unknown. I once received a single specimen among some small 

 American sea shells. {Kiister.) 



Phyaa semiplicata, KiisTER in Ch. ed. 2, p. 24, pi. iv, f. 7-9. 



I can give no information regarding this species further than 

 that contained in the original description and figure copied above. 



Ml 



