PALUDESTRINA JENKINSI NEAR HULL. 
BY) De ETCH. sbsAccbese. 
N September 3rd, 1900, Mr. F. W. Fierke showed me 
specimens of a AHydrobia from the Humber Bank, 
which differed from the common A. venfrosa, and had 
been taken in fresh water; and on visiting the spot on 
September ist, 1901, we found it fairly abundant on the 
Lemna and Myriophyllum. 
It proves to be Paludestrina jenkinst, a species described 
as new to science, in 1889, by Mr. E. A. Smith, from speci- 
mens found near Greenwich. As it was first found at Green- 
wich, Topsham, and Lewes, Mr. L. E. Adams enunciated 
the theory that it had been recently introduced with timber, 
probably from the Baltic, but Messrs. Kennard and Wood- 
ward state (Essex Nat. vol. xi. p. 290) that the shell has been 
obtained at a depth of two or three feet in the marsh clay of 
the Roding Valley, near Barking. They also show that it 
has been known since 1859, being figured by G. B. Sowerby 
under the name of Réssoa castanea (Jeffreys), whilst the 
Jeffreys’ collection contains specimens from Hampshire, 
labelled Hydrobia ferrusina. 
Since the publication of Mr. Smith’s paper (Journal of 
Conch, vol. vi. (1889), pp. 142-5), P. jenkinst has been 
found in several localities, many inland, in England, Wales, 
and Ireland, the only Yorkshire station, however, being near 
Middlesborough. The most peculiar feature of its re- 
discovery is its occurrence in abundance in districts which 
have been well worked by conchologists for many years. 
Near the coast it may have been taken as a variety of the 
common brackish water form P. ventrosa, as it was claimed 
to be by several in 1889, but it is difficult to see how it had 
been overlooked inland. Is it to be ranked with the periodi- 
cally disappearing species, A. glutinosa, L. glabra, &c.? 
I have examined all my specimens of Paludestrina, but 
find no jenkinsi amongst them. Ten years ago, when I in- 
vestigated every pond I could find in the district, I frequently 
tried this one but never obtained a shell of any description. 
The type form of P. jenkinsi is carinated, only 9% per 
cent. of the Topsham specimens being uncarinated (L. E. 
Adams, J. of C., vol. vii. p. 150). Very few of the Humber 
