Mr. W. Clark on some of the Animals of the Chemnitzise. 199 



head or rostrum, called by some naturalists the mentum, is, 

 when fully extended, rather long, very broad, square in front, 

 slightly emarginate in the centre, and on the march is always in 

 advance of the foot, as is usual with the muzzle of the Rissoce ; 

 it is grooved the whole length, and the groove is continued 

 towards the neck, just separating the tentacula at their basal 

 centre ; at its upper surface, close to the base, is the orifice of 

 the proboscis. The tentacula diverge to almost right angles, 

 and resemble short, broad, minute leaves, each with an opake 

 white stripe or stamen through the centre ; they bevel to a fine 

 edge, and with their large flexible margins can, like all the 

 Chemnitzice, simulate the ear-shaped folds characteristic of those 

 organs, which in this species are conspicuous, but the proteiform 

 tips are only slightly developed. The eyes are very black, not 

 quite close to each other, and immersed a little posterior to the 

 internal bases of the tentacula. The foot is rather long, extend- 

 ing to two volutions, very thin, in front bluntly auricled, termi- 

 nating, when in full march, in an acute point, and carries, on a 

 simple lobe at the junction of the foot with the body, a pyriform 

 light corneous operculum marked with arcuated oblique striae of 

 growth. The animal is free, creeps with rapidity, and dwells in 

 muddy ground mixed with shelly spoil in 14 fathoms water, off 

 Teignmouth, Devon. Malacologists will perceive that the organs 

 of this animal are in every respect generically the same as those 

 of Chemnitzia rufa and Ch. elegantissima. This species has never 

 before been observed alive. 



I have examined several live specimens of that variety of the 

 present species termed by authors Eulimella affinis, and I find 

 that the animal of the two is identical ; the only difference is in 

 the shell, which in the ' affinis ' is more taper, and has the 

 whorls more rounded and better defined by the divisional lines. 



Chemnitzia clavula. 

 Eulimella clavula, Brit. Moll. 



The animal inhabits a pearly white, but not glossy shell, of 

 five rather rounded volutions, including the moderately reflexed 

 apex ; the body is about half the entire length of the shell, with 

 a narrowish, elongated, oval aperture, quite free from angularity. 

 The animal is clear frosted white. Rostrum very narrow, rounded 

 at the end, not bilobed nor grooved, and carried just before the 

 foot ; neck greatly protruded, on the march showing an open 

 canal formed of two parallel longitudinal lines. Mantle even, no 

 fold visible. Tentacula short, broad, swelling out behind like a 

 minute wide leaf; the auriform folding nearly disappears on the 

 march ; they are not divergent ; indeed, I may say, they are 



