OP CONCHOLOGY. 33 



Julianehaab, near Narsak or Nordproven, (Holb. 1837). Moller 

 found it in a little lake on stones, covered with conferva, chiefly 

 on the under side, and in a tank at Kuksuk, on bullrush, Pota- 

 mogeton and the stems of Equisetum. At the latter place Mol- 

 ler obtained, by aid of the boatswain, some dozens of specimens, 

 but myriads of gnats prevented them from seeing, and forced 

 them to take to flight. 



LIMNiEA. 



Beck mentions, in his Index, 1837-38, for the first time, three 

 species of Limncea from Greenland, viz. : No. 11. L. Vahlii, B. ; 

 var. a laevigata, var. b incequalis. 12. L. Pingelii, B. 13. L. Hoi- 

 b'dlii, B. : a major, b minor. Some time afterwards one of the 

 varieties was distinguished in MSS. as L. Grrcenlandica, B., 

 probably the same mentioned in Jay's Catalogue, 1850, p. 269, 

 No. 6298. 



Beck communicated these names, probably from memory, to 

 Moller in such manner that the names of the Index and the 

 collection were confounded and perhaps even applied to species 

 unknown to Beck. As Beck has not described his species I 

 have, in the following, considered Mb'ller's Index as the starting 

 point, and used his typical collection and manuscripts. Mr. 

 Binney has lately given an account of the Greenland species of 

 Limncea from specimens " sent by Moller to the Smithsonian 

 Institution." This statement is probably erroneous, as Moller 

 died in 18-45, and, according to his diaries, he has never sent 

 any specimens to America. 1 suppose it is a collection from 

 the University Museum of Copenhagen, which I have named. 

 I mention this because some of the types of Moller are not 

 labelled, and I have only been able to identify them by aid of 

 the localities mentioned in his MSS. 



The Greenland species of Limncea belong to the section 

 Limnophysa, and have all an American facies except L. Holbol- 

 lii, which seems to me more like a gigantic L. truncatula ; but, 

 notwithstanding this different appearance, it is perhaps only a 

 variety of L. Vahlii. 



Although I have very few American specimens for compari- 

 son, I do not see any very striking difference between the Green- 

 land forms and L. elodes, Say, L. expansa, Haldem., or L. de- 

 cidiosa, Say. 



The most marked characters of the Greeland species are the 

 thinness of the shell and the colored bands of growth, reminding 

 one of the varices of the genus Triton. L. Vahlii thus has one 

 or two, rarely three, bands of growth ; L. Vahlii, var. /9, and L. 

 Holbullii generally five ; L. Pingelii four or five. 



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