` 
368 A Monograph of the Species of Pisidium. 
20 minimum, | deman, |Europe, 
21 minus, | timpson, |? . America, |Stimp. N. E. Moll. Cyclas minor. 
22 nitidum, | Jenyns, | Europe, Jenyns, Monog. Cyclas nitida. 
23 notatum, | Prime, . America, p Monog. 
24 Normandianum, | Dupuy, urope, ssies, Cat. “1849. 
25 nucleolus, Moricand, urope, | Mes [cum. 
obliquum, Pfeiffer, urope, | Pf. Sy ve Accord. 125. is P. amm- 
26 obtusale, Pfeiffer, urope, | Pf. Sy t. Accord. a C. obtusalis. 
27 obscurum, rime, America, | Bost. S É . Proc. iv. 161. 
al Nilsson, urope, |is amnicun 
28 Pfeifferi, iegler, urope, | Porro Malac. inflatu 
29 pulchellum, Jenyns, urope, | Jenyns, Monog .Q yclas foninals. 
30 pusillum, Jenyns, urope, | Jenyns, Monog. E c pusilla. 
31 riseum, | Scholtz, urope | m ltz, Cat. 
32 regulare, Prime, America, -| 
tundatum, Prime, (. America, Bost. S. N. H. pes iv. 164. [lum 
bellum, Prime, i. America, \. H. Pr. iv. 163. s E tenel- 
34 semen, lenke, w Holland, Menk. Moll Nov. Holl. 
supinum, chmidt, urope, Zeitschrift f. Malac 1850 
36 tenellum, ould, America, | Agassiz, L. Sup. P. rubellum 
37 variabile, me, . America, | Bost. S. N. H. Proc. iv. 168. 
8 ventricosum, rime, N. America, | Bost. S. N. H. Proc. iv. 68. 
39 zonatum, "rime, r America, | Bost. S. N. H. Proc. iv. 162. 
I am much indebted in the compilation of this list to the 
excellent Conchological Library of John C. Jay, M. D. of 
Rye, Westchester county, N. Y. There are, therefore, as 
may be seen by the above enumeration, thirty-nine known 
and identified species of Pisidium, to which number I add 
three more fossil species, from Germany, which are men- 
tioned in the Monograph of the Wealden of Northern Ger- 
many; their names, however, I do not know. Nineteen of 
these species, one fossil and the rest living, are found in the 
United States, one species is found in New Holland and the 
rest are natives of Europe. 
Of the American species, three, the P. Adamsii, P. ferru- 
gineum, P. ventricosum, are found but in New England; one, 
the P. dubium is found from Massachusetts, as far South as 
Maryland, and as far west as Wisconsin; five, the P. equi- 
laterale, P. minus, P. compressum, P. voriabil and P. zo- 
natum, are found in New England and in New York; one 
the P. altile is found in New York and in Ohio. The re- 
maining American species have as yet been noticed only in 
the localities where they were first discovered. . 
I will add, that I am preparing a Monograph of the species 
of Cyclas found in the United States, and that any information 
on the subject is courted and will be thankfully received. - 
