52 LITTOllIXID.E. 



Hydrobia ULv.^i"^, Pennant. 



Turho vlv(e, Penn. Br. Zool. iv. p. 132. t. Ixxrri. f. 120. Eissoa tdvce, F. 

 & H. iii. p. 141, pi. Ixxxi. f. 4. 5. 8, 9, pi. Ixxxvii. f. 2, 8, and (animal) 

 pi. JJ. f. 8. 



Body light- slatecolour, dark-grey, or sootcolour, with more 

 or less of a purple tinge, speckled with yellow, and having 

 occasionally a few markings of pm-ple-brown on the upper 

 part: paUial jjrocess thread-shaped, short, and cihated : snout 

 nearly cyhndrical, prominent, and extensile, cloven at the ex- 

 tremity, edged in front by a purpli.^^h -brown line, and having 

 two yellow spots in the middle : tentacles thread-shaped but 

 somewhat compressed, long, slender, and diverging, irregularly 

 speclded with yellow, raarked across a little below the tips by 

 a bar or ring of purplish -brown, and edged Avith the same 

 colour; they are covered -with fine and short, but not con- 

 spicuous, vibratile cilia, and often (especially the left-hand ten- 

 tacle) scalloped or serrated at the sides, like the weapon of a 

 sword-fish, apparently in consequence of voluntaiy contraction ; 

 tips rounded : eyes on small protuberances : foot lanceolate, 

 squarish and double-edged in front with short salient cor- 

 ners, narrower in the middle, and rounded behind ; it is mar- 

 gined with a narrow purplish-brown line ; sole hght-grey, mth 

 yellow specks : opercular lohe large and expanding on each 

 side, darkpurplish-brown ; it has no filament, process, or ap- 

 pendage of any kind. 



SuELL oblong, rather solid, opaque, and of a dullish hue : 

 sculpture, under a hand-lens exhibiting occasionally a few slight 

 spiral lines on the last whorl ; with a higher microscopic power 

 may be detected on all the whorls extremely fine, close-set and 

 numerous concentric wavy striae ; there are also the usual lon- 

 gitudinal lines of growth; the body-whorl is more or less 

 distinctly keeled in the middle : colour yellowish or reddish- 

 brown of various shades passing into horncolour : epklerrnis 

 very thin, and mostly obscure : spire rather long and tapering, 

 with a blunt tip : whorls 7-8, compressed, the last occupying 

 about one-half of the spire viewed in a supine position : suture 

 well-defined although not deep : mouth oval, narrowly an- 

 gulated above, and effuse or spread out below, where it is 

 also somewhat angular: outer lip thin and plain: inner lip 

 white, rcfle^ited on the pillar and over the base of the shell, 

 behind which it forms a small cleft or umbilical chink ; the 



* Inhabiting Ulva lactuca. 



