46 THE NAUTILUS. 
Binney and Bland collection seemed hardly quite like 
ovalis ; small, shiny, thin, rather greenish. 
Of these 33 nominal species of Suecinea, possibly not more than 
about half will prove valid, but it is impossible to arrive at any 
exact results without further research into the variation, anatomy 
and distribution of the several forms. 
The distribution, so far as known, present some features of 
interest. The species of the eastern and northern states are more 
like those of Europe than the southern or western. The southern 
and northwestern distribution of the campestres is noteworthy. It 
appears that in glacial times, owing to a warm current, the coast of 
Alaska was free from ice, while that of British Columbia was 
‘glaciated down to the sea’; hence a contingent of the campestres may 
have survived to the north, while their representatives in some of 
the middle regions were exterminated. 
While on the subject of Succinea, it may be worth while to call 
attention to fig. 13 of pl. Il, Bull, U. S. Geol. Survey, No. 34, 
(1886). The fossil there figured is referred by Dr. C. A. White 
with doubt to Limnea, but is it not a Succinea of the section 
Tnwcenee ? 
Regarding the Calif. Suce. stretchiana (Naut. VI, p. 72), I fear 
the specimens were in a box which unfortunately got lostin the 
post on its way back to Mr. Singley. They seemed to represent a 
distinct form, but it is possible that they were not true stretehiana. 
Bland’s type was from Washoe Co., Nevada; and no doubt the 
specimen from that locality in the Binney and Bland collection 
belonged to the original lot, the actual type being in U. 8. N. M. 
(see Man. Amer. Land Shells, p. 497). The Washoe Co. specimen 
examined by me was in some respects like avara, and by no means 
altogether like the Californian examples; but considering the 
variation seen in species of Succinea, I did not feel able to decide 
without better material, whether they should be held distinct, and 
so accepted the indication of the labels. There is a Colorado Sueci- 
nea which was formerly thought to be stretchiana, but it is certainly 
either a var. of avara or a species very closely allied. Is anyone 
prepared to say exactly what distinguishes stretehiana from other 
species? If the San Francisco specimens were not stretchiana, I am 
rather puzzled to know what are the true characters of the species. 
Perhaps the anatomy would settle the question. 
See Prestwich, Geology (1888) Vol. II, p. 464. 
