WITH A LIST OF SPECIES OBSERVED. 225
to an authority, who had pronounced them to be undoubtedly H.
similis.
This appeared to me to be conclusive evidence that the shells
were certainly the Hydrobia similis of Draparnaud, and from that
date until October 4th, 1889, I had no further doubt about them,
and during that period I sent out many exchanges of this species to
various correspondents.
To Mr. J. T. Marshall, of Torquay, belongs the credit of being
the first to positively say that it was not H. similis, although also for
a time he considered these shells to be Jeffreys' variety ovata of H.
ventrosa.3 These opinions of good conchologists must be my excuse
for being so easily misled in respect of this shell. Certainly, if I had
thought that there was the least doubt as to its identity, I should have
taken care to submit specimens for observation and comparison to
some practical conchologist well acquainted with the family. I also
regret that many correspondents have at various periods received as
an exchange these Hydrobia as authentic H. similis. I feel confident
that these mistakes originated owing to the great difficulty of obtain-
ing shells of H. similis, and also Jeffreys' variety ovata of H. ventrosa,
and I am certain that at that time the real Simon Pure was to be
found in the shell cabinets of very few collectors.4
As the dispute waxed warm between the advocates of H. jenkinsi
versus H ventrosa, var. ovata, I felt the necessity of procuring living
examples of all the species under discussion, and made frequent
excursions to the marshes in all sorts of weather. Having supplied
Mr. Smith, of the British Museum, with living examples of the three
species, I kept a number in Aquaria under my own observation for
many months. During this time I had every opportunity of noting
their difference in habit and capability of adapting themselves to
water which was more fresh or more brackish than that to which
they had hitherto been accustomed.
Close examination soon convinced me that Mr. Smith was right
3 This statement may be correct so far as the particular specimens sent to Mr. Marshall by his
correspondents as H. similis (" Journ. of Conchology," vol. vi., p. 140) were concerned; but it
seems to be clear that the credit of positively determining the Essex and Kent specimens as con-
stituting a new species belongs to Mr. E. A. Smith and Mr. Walter Crouch, who came to that
conclusion as long ago as February and, 1889. (Essex Nat., iv., pp. 212-214.)—Ed.
4 The first H. jenkinsi deposited in the collections at the British Museum were, we believe, the
three specimens sent on 29th January, 1889 (with other species of Hydrobia) by Mr. W. Allen, of
Canning Town, to Mr. Walter Crouch, who, noticing the carinated whorls, concluded at once
that they were new. They were taken on February 2nd by Mr. Crouch to the Museum, and Prof.
Flowers' acknowledgment, dated March nth, runs thus : "Three specimens of a species of
Hydrobia, new to the British fauna, from Beckton, near North Woolwich" (vide E. A. Smith,
"Journ. of Conchology," vol. vi., p. 142 ; Essex Nat., vol. iv., pp. 128 and 212 ; and "Science
Gossip," 1891, p. 163). Subsequently Mr. Jenkins sent a series from the Erith Marshes, and Mr.
Crouch a set of thirty-six examples from Beckton.—Ed.