Notes on Lingual Dentition of Mollusca. 2S9 



'• The locality in which I found the IleUclna occulta is a fishing 

 station known as Whitefish Bay, six miles north of this city 

 (Milwaukee, Wisconsin), on the slope of the lake blutf, which at 

 that point is somewhat wet and boggj'', with a growth of pines, 

 tamaracks, juniper, and some deciduous trees. They were under 

 dead leaves beside logs ; on the 30th of May and 6th of June, 

 1869, they were in considerable numbers, though they could 

 hardly be said to be abundant. I have not visited that place 

 since the latter date. On the 19th inst., however, I found a few 

 specimens in a ravine near the lake, about two miles and a half 

 north of the city — making in all some twenty-five specimens 

 found, among which are two young ones with an acute carina." 

 The locality is an interesting one, showing the possibility of a 

 tropical genus existing in a cold latitude. The discovery of Mr. 

 Leland is of far greater importance, however, in proving beyond 

 doubt the fact of Ilelicina occulta actually existing at the present 

 time. The species is found very plentifully in a fossil state in 

 the post-pleioceneof the Western States, and is generally supposed 

 to be extinct. Dr. Binney has (Terr. Moll. I., 183, 181) argued 

 at length against this opinion, and figured specimens apparently 

 recent (Ibid. III., pi. Ixxiv., fig. 1) ; he also referred to this species 

 the shell found living in Western Pennsylvania by Dr. Green, 

 and described by him as Ilelicina rubella. Specimens in an 

 apparently recent state have also been received by us from 

 Sheboygan, Wisconsin, and through the Smithsonian Institute 

 from Lexington, Virginia, collected in the latter locality by Mr. 

 McDonald. Fresh specimens were, however, so rare that belief 

 in the extinction of the species prevailed generally. Dr. Gould 

 referred (Terr. Moll. U. S., II., 352) Helicina rulella to Ilelicina 

 orhiculata^ a recent species found as far north as Tennessee, and 

 finally in the Land and Fresh-water Shells of North America. 

 Part III., Ilelicina occulta is removed from the catalogue of recent 

 species and quoted only among the fossils. 



Mr. Leland has now reversed this decision by finding the 

 animal actually living. It is in consequence fair to presume that 



