36 Moll. 
MOLLUSCA. 
Historical Changes and Acclimatation. 
Lithoglyphus naticoides (Fer.) found in the summer of 1883 near Kus- 
trin by Heinrich Schulze, near Berlin by Oswald Schulze, and near 
Danzig by E. Schumann ; also a dead specimen near Thorn in 1882 by E. 
Friedel. As there is no probability that this very peculiar shell should 
have been overlooked by former authors, it seems a second example of 
contemporaneous immigration from the south-east, similar to that of 
Dreissena polymorpha. Martens, SB. nat. Fr. 1883, pp. 100-102, and 
Friedel, Nachr. mal. Ges. 1883, pp. 183-180. 
F. T. Koppen points out how far Dreissena polymorpha (Pall.) was 
distributed in Europe in Pliocene and Plistocene times, and how it has 
regained in the present century a more general distribution throughout a 
large part of Europe ; he has collected for this purpose a considerable 
amount of information additional to that given by the Recorder in Zool. 
Gart. 1865, and thinks that the original habitat of this species is the Caspian 
Sea, from whence it migrated northward and westward by the Volga and 
its Oka confluent : title, supra , p. 7. The same alluded to by Neiiring, 
SB. nat. Fr. 1883, pp. 68 & 69. This species now also found at Basel ; 
Sterki, Nachr. mal. Ges. 1883, p. 74. 
Helix pomatia. Some traditions concerning its introduction into 
England mentioned by W. C. Atkinson, Nature, xxviii. p. 81. 
Helix acuta (Mull.) and candicans (Ziegl.), imported at Frankfort, 
became extinct within two years ; Kobelt, JB. mal. Ges. x. p. 99. The 
former ( Bulimus acutus ) found in a garden at Collingwood, New South 
Wales, introduced from France ; Abstract of P. Linn. Soc. N. S. W. 
July, 1883, p. iii. 
Alterations in the Molluscan fauna of a small pond, in which 5 species 
of fresh- water shells were found in 1884, though not in 1860-63 ; W. Nel- 
son, J. of Conch, iv. p. 117. 
Decrease of Physa guadeloupensis (Fischer) in number and size of late 
years ; Maz^:, J. de Conch, xxxi. p. 31. 
Bithynia tentaculata (L.) found recently at Burlington, Vermont, and 
very abundant in the Mohawk, where it was planted by J. Lewis ; A. F. 
Gray, Am. Nat. xvii. p. 205. 
Margaritana margaritifera (L.) found in Anticosti in 1881, but not 
in 1861, by Prof. Hyatt ; Nachr. mal. Ges. 1883, p. 93. 
Unio pressus (Lea), originally described from the Ohio, has recently 
been found in the States of New York and Vermont and in Canada ; pro- 
bably it extends its area first by the agency of water-fowl, and then by 
following the currents of the rivers and the shores of the lakes : A. F. 
Gray, Am. Nat. xvii. p. 205, and W. M. Beauchamp, l. c. p. 434. 
Immigration of littoral shells by the Suez channel, Gardium edule in 
the Timsah Lakes, Mactra olorina and Mytilus variabilis , from the Red 
Sea, in Lake Menzaleh, &c. : C. Keller, Denk. schw. Ges. xxviii. pt. 2, 
1882, pp. 23-26 ; abstract in Nachr. mal. Ges. 1883, p. 117. 
