164 
LIMNiEA STAGNALIS (LINN.) 
July, 1889. 
TWO HITHERTO UNDESORIBED VARIETIES OF 
LIMNiEA STAGNALIS (LINN.) 
BY JOSEPH W. WILLIAMS. 
AUTHOR OF “THE SHELL-COLLECTOR’S HANDBOOK FOR THE FIELD,” “LAND 
AND FRESH-WATER SHELLS,” ETC. 
I do not hold with giving special variety-names to colour- 
variations in the shells of land and fresh-water Mollusca, 
neither do I hold with defining as var. major, maxima, minor , 
or minima shells which differ only from the type-form in 
largeness or littleness respectively. The colour of the 
former class can be as well expressed in our native tongue, 
and the size of the latter can be far better given in terms of 
measurement. For example, it is as well to say a white 
Helix nemoralis as to say Helix nemoralis var. albescens (Moq.», 
and it serves the scientific purpose better to give the height 
of a form in measurement than to describe it as var. major , 
or var. minor, which may be anything above or below a 
certain set number of millimetres. I have stated my views 
on variety-naming in a series of four papers to “ Science 
Gossip ,” on “ Variation in the Mollusca and its Probable 
Cause,”—the first part of which, the editor writes me, will 
appear in the July number,- and to these papers I must 
refer the reader for an extension of these my views on variety¬ 
naming. But I consider, on the other hand, that when a 
form is found differing from the type by a combination of 
structural characters of shell, it is as well that a special variety 
name be appended to it. To this class of varieties the two 
forms of shell of Limncea stagnalis I am now going to describe 
are to be relegated. I propose to give to them the special 
variety-names of eleyans and contortiila. 
Variety eleyans .—Height, 35 mill. ; breadth of body-whorl, 
15 mill. Whitish in colour; aperture small, rounded, inner lip 
(“parietal wall ” of Pfeiffer) well pronounced; spire elong¬ 
ated, suture deeper than in type, subscalariform, in general 
run of spire somewhat like that of the marine shell Turritella 
replicata (Linn.); body-wliorl not babylonic, shorter than in 
type (f total length of shell) and revolving more evenly ; suture 
between the body-whorl and the whorl immediately preceding 
it deeply and triangularly canaliculate. Locality.—Pond in 
field off Platt’s Lane, Hampstead, London. Given to the 
describer by Mr. G. K. Gude, by whom it was collected. 
