HERTFORDSHIRE MOLLUSC A. 
13 
Paludina vivipara (Z.). 
D. Cooper in 1836 recorded P. achatina ( = P. vivipara) as having 
been found in the “ New River ” by Thomas Bell. 
Paludlna yiyipara (Z.), var. efasciata, Pick. 
Mr. Pickering described this form in the ‘Zoologist’ for 1847, 
saying of it: “ The shell is very local, and by no means plentiful. 
I have taken it in slow streams in Hertfordshire for the last three 
years successively, but nowhere else. I have never met with any 
specimens that are intermediate between it and the strongly-banded 
ones, but, on the contrary, all the other specimens I have taken 
associated with it are the most strongly banded I have ever seen.” 
Porbes and Hanley state that “A greenish white variety, without 
bands, has been found by Mr. Pickering, in the river Lea, Herts,” 
but they erroneously refer this variety to their P. Listen {contecta ) 
instead of to this species. Dr. Jeffreys calls the variety unicolor , 
and observes: ‘ ‘ The variety has been found by Mr. Pickering in 
Hertfordshire.” Mr. Taylor in 1883 corrects Jeffreys’ nomencla¬ 
ture as to this variety, and reproduces Pickering’s original obser¬ 
vations.*' 
Dreisseha polymorph a {Pall.'). 
Dr. Jeffreys says that this species “ has been found in the most 
frequented streets of London, after they have been flushed with 
water from the New Biver, where it abounds.” 
Neritiha fluviatilis (Z.). 
Recorded in 1836 by D. Cooper as found “in the Thames and 
Lea abundantly ” by James Carter, Thomas Bell, and himself. 
Plahorbis carihatus, Mull. ; P. corheus (Z.). 
Mr. H. J. J. Lavis found these in 1875, together with Physa 
fontinalis , Limncea peregra , and Z. stagnalis , “in a pond by the side 
of the road, just after crossing the river bridge (Bushey Mill).” 
Physa fontihalis (Z.). 
Pound by Mr. Lavis at Bushey Mill in 1875, with the preceding. 
Limh^ia auricularia (Z.). 
Recorded in 1836 by D. Cooper as found “in Lea River ” by 
Thomas Bell. 
Limh^a peregra {Mull.) ; L. staghalis (Z.). 
Both these species were found by Mr. Lavis at Bushey Mill in 
1875 in company with the Planorles, etc., and in 1883 they are 
recorded for Puckeridge by Loydell and Rowe. The last-named 
species in its juvenile stage is probably the Limneus Scaturiginum 
which in 1836 Daniel Cooper recorded as having been found in the 
“New River ” by James Carter. 
Limislea staghalis, var. fragilis (Z.). 
R. Tate remarks: “The variety is found in a few canals. I 
have met with it very elongated in the River Lea, at St. Albans.” 
[The river is the Yer.— Ed.] 
* Dr. Jeffreys informs me that when he gave the name unicolor he was not 
aware of Mr. Pickering’s publication, having received specimens from him without 
a name.— Ed. 
