Mr. W. Clark on some of the Animals of the Chemnitzise. 207 



Chemnitaia acuta, mihi, Ann. Nat. Hist. N. S. vol. vi. p. 452. 



Odostomia acuta^ auct. 

 O. conspicuaj Alder ? 

 O. turritUy nonnull. 

 O. striolattty Alder ? 



Animal inhabiting a glossy shell of 5-6 rounded volutions of 

 a more or less pale livid red^ pinkish, or pearly hue ; the apex is 

 greatly reflexed, and the aperture furnished with a conspicuous 

 tooth. The ground colour of the animal is a sordid white, mixed 

 with clouded pale yellow, red, or brown patches and points, 

 which are irregularly distributed on many of the organs ; the 

 tissue of the skin is smooth, rarely frosted or breaking into a 

 mottled flaky aspect. The mantle is even, except that at the 

 upper angle of the aperture, there is a very evident folded 

 tubular canal, which I have alluded to in the preliminary obser- 

 vations on the genus. I will only add, Mr. Lowe writes, " pallio 

 ecanaliculato ;'^ M. Loven says, "processus pallii dexter canali- 

 culatus ;" from which it may be inferred that the canal is some- 

 times present, at others not, or not visible. The rostrum is 

 slender, deeply channelled, or hollowed out its whole length, 

 having a cochleariform termination, and at the upper surface of 

 its base emits the proboscis. The tentacula are moderately long, 

 divergent, subtriangular, bevelled, with the margins only slightly 

 folded, and the tips are less white and inflated than usual ; the 

 eyes are rather close at the internal angles. Foot short, opake 

 white, often aspersed on both surfaces with the varying hues I 

 have spoken of above, deeply hollowed out in front, forming with 

 the angles long auricles, which, when drawn together by the 

 animal, have the appearance of a second pair of tentacula ; its 

 posteal termination, at the will of the animal, assumes the varying 

 phases of the pointed and obtuse forms, carrying at the junction 

 of the foot with the body, on a simple eminence, a pyriform red- 

 brown or yellowish obliquely striated operculum. 



There being some inaccuracies in my account of the Ch. acuta 

 in the ' Annals ' referred to above, I have reproduced it, as it is 

 an important species embracing several others of doubtful pa- 

 rentage, and some varieties, which latter produce the three fol- 

 lowing distinct forms. The slender subcylindrical variety passes 

 in all collections for the coralline zone Ch. plicata ; this is an 

 error : an examination of the animal shows it to be a Ch. acuta, 

 differing materially in its organs from the true ^plicata* which 

 is essentially a littoral animal, rarely, if ever, found beyond that 

 limit : I have hundreds of examples taken alive. The next form 

 is that of the common livid flesh or pearl-coloured glossy shell 



