26 LAXD AND FRESH- WATER SHELLS OF N. A. [PART II. 



of States, to the Pacific Ocean. It is also foaucl in Oregon 

 and southern Utah, though it occurs most plentifully in the lake 

 region of British America. Specimens of it have been collected 

 for the Smithsonian Institution by Mr. Kennicott, at Fort Reso- 

 lution and Fort Simpson, and at Moose Factory, by Mr. Drexler. 



From the means of comparison at my disposal I have no doubt 

 of the identity of the European Limnsea stagnaJis with this shell. 

 Their proving to be the same will add another to the list of 

 circumpolar species common to the two continents. 



Authentic specimens of Mr. Say's L. appi-essa are still pre- 

 served in the collection of the Philadelphia Academy. They 

 correspond well, though smaller, with the figure of aj^ptx^ssa 

 (Fig. 28), which I have copied from Haldeman. I have seen no 

 authentic specimen of Say's L. jugularis, but have no doubt of 

 its identity with the shell he afterwards called appressa, not only 

 from his comparison of jugularis to stagnalis, but from the tra- 

 dition of the earlier collectors, who always have considered them 

 nearly related, if not the same. Mr. Say's description of jugu- 

 laris, in the third edition of Nicholson's Encyclopedia (which is 

 reprinted in my edition of his works), is extremely unsatisfactory, 

 and would hardly be referred to the shell before me, without the 

 words used by him in the first edition. Both are now given. 



There is a species of this genus which resembles the fstar/nalis of Europe : 

 we have named it Limnxa jugularis. Whirls about six, tapering ; mouth 

 within often brownish, lip white, column a little contracted in the middle ; 

 we have not a good specimen to describe or figure. {Say, Nich. Encycl. 

 first ed.) 



There is a species of this genus that we have named Limnsea jugularis, 

 and which, in consequence of its having been found but once, must be 

 considered as a doubtful inhabitant of the United States. It may thus be 

 described : Shell tapering ; whirls about six ; suture not deeply impressed ; 

 aperture hardly equal to half the length of the shell, but little dilated ; 

 within brownish, particularly on the column, which is contracted in the 

 middle ; outer lip white, and almost imperceptibly repand within ; um- 

 bilicus very distinct. Length one inch. A specimen was also brought 

 from the West Indies, by Mr. L'Herminier, of Charleston. (.Say, od ed. 

 I\ich. E lie yd.') 



Haldeman admits L. appressa as a distinct species with doubt, 

 but describes it as more attenuated, lighter in color, and having 

 the spiral striae better developed than the typical JitgrwZaris. One 

 of his figures of the latter is copied in my figure (Fig. 20). 



