LIMN.EA. 



55 



Tliis little Limnaa is but slightly veiitricose ; the aperture is hardly as 

 large as in the following species (Z>. naciculn). Tlie height of the last 

 whirl is double that of the four other whirls taken together. Whirls with 

 tine striae pftallel to the right lip. Aperture oval, its vertical diameter 

 equalling two-thirds of that of the last whirl; breadth only one-half the 

 length. 



Color yellowish horn. Length 9 lines. Environs of Philadelphia. 

 ( Valenciennes.) 



1 have seen no autlientic specimen of L. virginiana, and should 

 hardly refer it to this species. It is, however, doubtfully placed 

 in the synonymy by Ilaldeman. The original description of 

 Lamarck and figures of Delessert here follow. It is referred to 

 L columella in Beck's Index. Dr. Gould tells me that speci- 

 mens of L. columella, in the Leyden Museum, are labelled L. 

 virginiana. 



Limnapa virginiana, Lamarck. — Shell ovate-ventricose, very thin, diapha- 

 nous, longitudinally wrinkled, grayish ; 

 whirls five, the last longer than the spire ; Fig. 84. 



labrum turned backwards. 



Hab. Fresh-waters of Virginia. Its thin- 

 ness renders it very fragile. 15 lines long. 

 (^La/narck.) 



In addition to the synonymy already 

 given above, Haldeman and DeKay re- 

 fer to this species L. decollata (q. v.). 

 Lewis (Bost. Proc. \I, 122) places 

 L. cafascophnn and emarginafa in the Ltmncea virginiana. 



synonymy of L. elodes. Kiister, I. c, 



quotes, as synonyms of L. catascoj)ium, the following : L. pinguis, 

 L. cornea, L. virginiana. 



Fig. 80 and 82 are fac-similes of those of Mr. Say. Fig. 81 

 is from a specimen taken in the Delaware River. 



The lingual dentition of Limnaea catascopium is figured in 

 Fig. 85. There are 105 rows of teeth, 34 laterals in each row. 



Fig. 85. 



Lingoal dentition of Limn(£a catascopium. 



