4 THE NAUTILUS. 
of the same genus which may be new. Also a small white Physa 
which is provisionally referred to P.gyrina Say. A small elongated 
Limnea of the refleca group from the same locality, seems to be 
the L. lanceata Gld. No less than seven different species of Lim- 
neidae, six of operculates, and many Pisidia were brought up by 
one haul of the trawl from this prolific locality. In a small lake 
near the south end of Beaver Island, which was simply swarming 
with animal life, were found the finest specimens of Limnea ampla 
Migh. yet seen from Michigan. The largest example collected 
measured 283 mm. in length and 19 mm. in breadth, the aperture 
being 19 ? mm. long and 13 mm. broad. 
The Limneidae of Pine Lake, which empties into Lake Michigan 
at Charlevoix, were also extremely interesting. The bottom of the 
lake is composed almost wholly of marl, except where it has been 
covered by a thin coating of sand washed in from the shores, and, 
as a consequence, both plant and animal life exist under very un- 
favorable circumstances. The level of the lake seems to have been 
lowered by the canal made by the U. S. Government to connect it 
with Lake Michigan, and the former lake terrace is now largely ex- 
posed, and, in many places, quite dry. In the numerous pools, how- 
ever, which are left along the shore, the Limnwa catascopiuwm Say is 
found in great abundance and almost infinite variety. It varies in 
shape from the comparatively slender form usually found in the 
Great Lakes to the globose form described as L. pinguis by Say, and 
seems, in many cases, to run very close to that of LZ. ample Migh. 
The Pine Lake examples have usually a very thick, solid opaque 
shell, and a large proportion are more or less distorted, the most 
common effect of their unfavorable environment being apparently 
to induce a very abrupt and rapid expansion of the outer lip, which, 
in most cases, is accompanied by a heavy callous deposit all round 
the aperture. The dredge also brought up from the marl of the 
bottom some other curiously distorted forms of Limnea, whose 
specific position has not yet been satisfactorily determined. The 
curious Planorbis multivolvis Case also occurred here, rarely alive, 
but in great abundance among the dead shells along the shore. 
There is reason to suppose that these shells came largely from the 
marl deposits under the lake. It also seems probable that this 
species will prove to be only a form of P. campanulatus Say, pecu- 
liar to localities where the mar] is found. At any rate, all the lo- 
calities in this State, from which it is now known, are alike in this 
i gs a es 
