62 LAND AND FRESH WATER MOLLUSKS 



The name Lymncea has been spelled in many different wa} r s, the 

 most correct being Limn&a, but there seems to be no good reason for 

 changing the original form, especially as no derivation was given by 

 Lamarck. The Helix stagnalis of Linne, being the only species 

 mentioned, necessarily becomes the type. 



Four years after Lamarck, Schrank gave the name Galba to a 

 species which was without doubt the Buccinum truncatulum of 

 Muller. It has been referred to B. palustre Muller, but a scrutiny of 

 the very careful description of both shell and animal reveals that it 

 agrees with no local species of the group except a young truncatula. 

 A little later Montfort separated the L. auricular ia group under the 

 name of Radix, and in 1819 Rafinesque, in a summary of the forms 

 collected on the Ohio River, proposed Omphiscola for species which 

 have the peristome reflected over the pillar and body with an umbilical 

 chink between the reflection and the body of the shell. He cites no 

 species, but of the Ohio species only L. rejlexa Say can be said to 

 agree with the diagnosis. This character is however of minor impor- 

 tance. Rafinesque's name has been applied to several European 

 species but without adequate grounds, since there is no species of the 

 Radix group known in any part of the Ohio system. 



The name Stagnicola Leach was cited in synonymy by Jeffreys in 

 1830, in connection with L. palustris (Muller) , thus antedating Lim- 

 nophysa Fitzinger, 1833, based on the same type. Stagnicola was 

 used by Brehm for a bird in December, 1830, but Jeffreys' paper was 

 issued May 29. Both these names have been loosely used in the lit- 

 erature, but must be restricted to the typical and original forms. If 

 the columnar species like L. glaber be separated in a section by them- 

 selves, Leptolimnea Swainson appears to be the first available name. 

 Erinna Adams is a Limnaeid modified for existence on rocks in rapid 

 streams and waterfalls, the peristome being continued over the body 

 and behind the broad excavated pillar, and the spire shortened, so that 

 the animal may cling tightly to its situs. The descriptions of this 

 form are rather misleading, the so-called ' lamina ' being merely the 

 pillar. The fossil Velutinopsis is more like Choanomphalus than 

 Lymncea, judging by the figures. The description of Tanousia reads 

 as if it was founded upon an abnormal or monstrous specimen. The 

 reversed physiform Lymncea of the South Sea Islands will be included 

 under Physastra Tapparone-Canefri ; a species from Hawaii which 

 is dextral but may be otherwise similar, has recently been shown by 

 Pilsbry to have a somewhat different radula from the ordinary Lyrn- 

 ncea of north Europe and America. 



