40 
THE - CONCHOLOGISTS’ - EXCHANGE, 
able conditions as well; some species preferring 
beds of sand or fine gravel, others of mud, &c. 
Nowhere in the Park, perhaps, are all of these 
conditions so favorable as upon the breast of 
Fairmount dam when the coping is a foot or so 
above the water, which is then about the same 
indepth. Unfortunately for the collector, the 
dam has been submerged during the most of the 
Summer, but the coping and ‘overshute”’ are 
both diy at present’and will probably remain 
so during September and October. At this 
point, in the Summer of 1885, I secured on one 
occasion eleven different species, all alive and 
in excellent form, ‘These were /Vanorbis tr7- 
volvis, Planorbis bicarinatus, Vivipara decisa, 
Vivipara subcarinata, Somatogyrus altilus, 
Amnicola limosa, Melania virginica, Physa 
heterostropha, Spharium similis, Spherium sut- 
catum, and Pisidium abditum, A majority of 
the species were abundant, and in all stages of 
growth. 
L.. Ogden, Chief of the Water Department, but a 
note to his address, 13th and Spring Garden 
Sts.. will doubtless bring a favorable response. 
The former feeding grounds of Spherium 
similis, below the sewer opening under Girard 
Avenue bridge, have been nearly buried by the 
“Land Makers” of the Park. At this locality 
I have collected large numbers of perfect spec- 
imens, and it is just possible that some may 
still be found there. I have never seen them 
in the Schuylkill except at this point, and upon 
the dam breast, as before mentioned. /2szd- 
‘um abditum, though not plentiful, were associ- 
ated with them in both places. Several of the 
other species named can still be collected here, 
On the flats fronting the river road above the 
tunnel, Limca desidiosa may be seen delving 
in the mud as of old, although a fine colony of 
Valvata tricarinatus, which formerly inhabited 
the southernmost flat, no longer exists; the bed 
of fine gravel on which they flourished having 
been buried under the new roadway. A few 
can still be found on the little patches of sand 
scattered along both sides of the river, but their 
days are evidently numbered. ‘The “ March of 
Improvement”’ will soon obliterate these favor- 
ite haunts, and with their destruction the species 
will, probably, disappear altogether from the 
Park. 
Of course, persons are not allowed | 
on the dam except by permission of Mr. Jno. 
On the same side of the river, midway be- 
tween the Girard Avenue and Columbia bridges, 
Ancylus rivularis makes its home during the 
Summer months. ‘This species also inhabits the 
lily ponds south of Horticultural Hall. In 
the river it should be sought for on submerged 
stones and bits of wood; in the ponds, under- 
neath the floating leaves. Good specimens of 
other species may also be gathered at various 
| points along this side of the river between the 
two bridges. 
The shore at Robinson’s knoll, near the 
mouth of the Wissahickon, though a favorite 
resort of collectors, yields but a few species. 
They are generally in good condition, however, 
and so are well worth looking for. In the 
Wissahickon above the dam I have taken num- 
bers of Planorbis parvus and Physa heterostro- 
pha, but have seen no other species in the 
vicinity. 
It is said that at least two species of Am- 
nicola flourish among the stones higher up the 
stream, and this statement may be correct, 
though I have searched for them there many 
times without success. Of the western side of 
the river from Chamouni to Columbia bridge I 
know very little. The same may be said in 
regard to the shores of Peter’s Island. Still, 
as the littoral conditions of this island appear 
from a distance much like those of the adjacent 
island known as Belmont Landing, I would not 
be surprised to learn that a number of species, 
including several of the genus (70, were living 
there. But however plentiful they may prove to 
be, it is hardly probable that they will surpass in 
numbers or perfection those strewn at times 
upon the river shore of the last named island. 
A few days ago Mr. John H. Campbell and 
myself collected here a majority of the species 
I have named, together with (720 comflanatus, 
Unio nasutus, and Anodonta fluviatilis. All 
were what are known as “dead shells,” but as 
they had been driven under the bushes by the 
steamboat waves, and thus not exposed to the 
sun, the most of them were in excellent condi- 
tion; both species of 7v7para being unusually 
large and fine. ‘The localities referred to are 
near the ends of the island, both the upper and 
the lower, although several species can always 
be found on the little sand slip adjoining the 
north side of the wharf. The Somatogyrus 
