442 PYEAMIDELLID^E. 



Exmouth, June 15th, 1853. 



A lively specimen shows that the foot is deeply notched in 

 front, forming divergent acute auricles, instead of being 

 gently concave ; when fully extended, it reaches to the second 

 volution, terminating in two symmetrical distinct pointed 

 tails or streamers, which describe an angle of separation 

 equal to that of the fore and middle fingers when placed 

 as far apart as possible. This structure is of normal cha- 

 racter, and not a mere emargination. 



CH. OBLIQUA, Alder. 



Odostomia obliqua, Alder. 



-, Brit. Moll. iii. p. 291, pi. 96. f. 1 ; and iv. p. 280. 



The animal inhabits a very pale yellowish- white smooth shell 

 of four rather tumid volutions, besides the apical reflexion, 

 which is less than usual ; the divisional lines are by no means 

 oblique, and the body exceeds the length of the spire; its 

 colour is a brilliant frosted subhyaline-white. The mantle is 

 even, except a conspicuous tubular fold at the upper angle of 

 the aperture. The rostrum is short and cloven in the centre 

 almost to the eyes : each segment forms an arcuation to each 

 side equal to an angle of 40. The tentacula are strong, 

 rather long, without much auriform folding, subrotund and 

 taper, terminating with minute circular snow-white spots or 

 inflations on the tips; the eyes are close together at the 

 internal basal angles : the great peculiarity attached to the 

 tentacula is, that instead of a moderate divergence on each 

 side the rostrum, they form large arcuations, and are carried 

 at right angles to the axis of the shell. Foot thin, rather 

 concave in front, slightly auricled, long and broad, and, when 

 fully extended, reaching beyond the body whorl, terminating 

 in a distinct bifurcation, which is very apparent in slow march, 

 but on a quicker pace being attained, the fork in some mea- 

 sure decreases in consequence of the greater extension of the 

 foot : on a small simple lobe, close to the junction of the 

 foot with the body, is fixed an elongated, narrow, corneous, 

 delicate light yellow operculum with close-set oblique stride of 

 growth. 



