KENNAED & WOODWARD : OjST TWO PALTTDESTEIN^. 299 



could not include them in the English Molluscan fauna, and added 

 that repeated search in the same locality had failed to find any more 

 examples.^ Since Sowerby's figure somewhat resembles Paludestrina 

 Jenlcinsi, there seemed a probability that the species might be 

 represented in the Jeffreys Collection, now alas ! , at Washington, so 

 examples were forwarded to Dr. W. H. Dall, who most kindly 

 replied that while he has failed to trace any example of the Rissoa 

 castmiea in that collection, there were two examples agreeing in every 

 respect with the specimens of Paludestrina Jenkinsi forwarded, and 

 labelled ^'' Sydrolia ferrusina, Hampshire, Sowerby." There can be 

 no doubt that these are the shells which Jeffreys states had been sent 

 to him some years ago by the late Gr. B. Sowerby, from that county.^ 

 Additional proof is thus furnished that the shell has been both 

 overlooked and misidentified. 



Paltjdestkina confusa (Frauenf.). 



The first accurate record of this species for England was in 1840,^ 

 when Dr. J. E. Gray noted it, under the name of Littorina anatma, 

 Drap., as occurring in the marshes at Greenwich with Assiminea 

 Grayana, Leach, and pointed out the differences between it and 

 Bythinia ventricosa. In 1853 it was figured as Rissoa anatina, Drap. ?, 

 and a description of the animal given by Eorbes and Hanley,* who 

 state that their examples were sent them by Mr. Pickering. They 

 further remark that it was rare in the marshes near Greenwich. 



J. Gwyn Jeffreys in 1862 noted that its habitat was in "muddy 

 ditches which are occasionally overflowed by the tide of the Thames 

 from Greenwich to below Woolwich," and he also noted that it had 

 been found by Mr. Prestwich and Mr. Pickering in peat in the main 

 drainage cutting between Woolwich Arsenal and Crossness.^ Mr. J. T. 

 Marshall informs us that about 1870 it occurred between Erith and 

 Abbey Wood, and also at Tilbury. Since then extensive building 

 and draining operations have entirely changed the aspect of things, 

 and between 1889 and 1893, when systematic search was made for 

 this species, it was only taken in four localities — a single dead shell at 

 Beckton, one dead and two live shells near Abbey Wood, one live shell 

 between Erith and Dartford Creek, and numerous examples from 

 a small ditch about half a mile west of Erith. In 1895 we took 

 a single live specimen from the last-named locality. The ditch has 

 now become dry, and no living example having since been found 

 in the district, the mollusc must, we are afraid, be now considered 

 extinct, though there is yet a possibility it may be found in some 



1 British Conchology, vol. i, pp. 68, 69. 



- Ibid., p. 69. 



3 W. Turton: "A Manual of the Land and Fresh-wafcer Shells of the British 



Islands," 1840, p. 87. 

 * " History of British Mollusca," vol. iii (1853), p. 134, pi. Ixxxvii, figs. 3, 4. 

 5. British Conchology, vol. i, pp. 64, 65. 



