Bibliographical Notice. 493 



come to his notice, but the paper was not pubhshed until this year 

 (Zool. Gart. Frankf. 1865, pp. 50-59, 89-97). Dreissena poly- 

 morpha is, according to Hr. Merian {I. c.) accompanied by Neritina 

 fiuviatilis in the Upper Rhine, where it never occurred before. The 

 Recorder is enabled to confirm this by a communication from Prof. 

 Braun, who says that it was not found in the Rhine near Carlsruhe 

 some twenty years ago " (pp. 191-192). 



In the second volume of the 'Record,' pp. 216-217, we have the 

 following additional particulars on this most interesting subject: — 



" Martens, E. v. Eine eingewanderte Muschel. Zoolog. Gart. 

 Frankf. 1865, pp. 50-59, 89-95. Dreissena polymorpha was not 

 known in the northern and western halves of Europe some forty 

 years ago. The numerous treatises on the moUusk-faunas of these 

 countries published at the close of the past and in the first two 

 decades of the present century do not mention it. All at once it 

 was observed for the first time in tributaries of the Baltic, the 

 Niemen and Weichsel, in the year 1825, in tributaries of the Elbe in 

 1828, in the terminal branches of the Rhine in 1826, and in England 

 in 1824. Several direct observations, and the comparison of the 

 localities and times in which it has been observed for the first time 

 in the several countries, establish the fact that it has been introduced 

 into all those parts of Europe, along artificial, navigable canals, by 

 means of ships or timber, and even across the Channel to England. 

 The belief that it was observed already towards the close of the past 

 century in south-western Germany is founded on a very superficial 

 description of a shell by Sander and contradicted by the negative 

 evidence given by Prof. Alex. Braun for the years 1824-46, and by 

 Hr. Gysser for the present time, both agreeing in never having met with 

 Dreissena in that part of Germany. As regards the rivers near to the 

 Black and Caspian Seas, no reliable or sufficiently complete record 

 of their faunas has been preserved from the commencement of this 

 century ; and there is consequently no reason to think that a 

 recent migration has taken place into the Danube and the rivers of 

 Southern Russia. At present it inhabits nearly all the tributaries 

 of the Baltic, the Elbe upwards to Halle, the Rhine upwards to 

 Huningue, the rivers of northern France, including the Loire, the 

 British Islands, Hungary, a part of European Turkey, and almost 

 the whole of Russia. It is very desirable that the attention of 

 conchologists should be directed to the further advance of this shell, 

 and that accurate statements should be made as regards the time 

 at which it first appears in the lists of local faunas, not having been 

 mentioned by previous accurate observers. This species is really a 

 freshwater shell ; it does not live in the Baltic itself, but only in the 

 brackish water near the mouths of the rivers. The breakwater 

 leading to the lighthouse at Swinemiinde, for instance, is occupied 

 on the river side by Dreissena, on the sea side by Mytilus edulis. 



" Hr. Jackel, Hr. C. Staude, and Dr. Fr. Buchenau have con- 

 tributed fiirther observations on this subject in the same journal, 

 pp. 196, 228, and 278, in which they state that this shell is found 

 at present in the Weser and in the Bavarian tributaries of the Main, 



Ann. &^ Mag. N. Hist. Ser. 3. Vol. xviii. 34 



