TRUNCATELLA. 85 



Truncatella trunca'tula "^^ Draparnand. 



Cydo&toma truncatulum, Drap. Tabl. Moll. p. 115. T. Montagici, F. & H. 

 iii. p. 317, pi. xcix. f. 1, and (animal) pi. FF. f. 10. 



Body very pale yellowish-white, with grey specks : snout 

 long, narrow, and very extensile, annulated when at rest, 

 aui'icled at each end ; it is finely grooved down the middle : 

 tentacles short, hroad, flat, and somewhat triangular : eyes hlack, 

 with white pupils, on expansions of the tentacles : foot roundish- 

 oval and thick. 



Shell forming a short and turreted cylinder, nearly equal 

 in breadth throughout ; it is rather thin, semitransparent, and 

 glossy : sculpture sometimes none, in other specimens more or 

 less distinct and strong longitudinal ribs on all or part of the 

 whorls ; under a good magnifier may also be detected faint 

 traces of spiral and close-set striae : colour pale yellowish-brown 

 or ta^aiy, with a creamy tint : spire having an extremely blunt 

 tip in the young, and abruptly truncated in the adult ; the 

 Hue of fracture where the first-formed whorls were rubbed off 

 is conspicuous : whorls 6| in the young, and 3| only in the 

 adult ; although rounded they are compressed, especially in 

 the naiddle of each, and increase very gradually, the penulti- 

 mate whorl being in fact a trifle broader than the last ; the 

 original whorls are fragile, and (like the milk-teeth of certain 

 Mammalia) deciduous at the proper season : suture deep : 

 mouth small in comparison with the size of the last whorl ; it 

 is somewhat contracted above, rounded and expanded below : 

 outer Up reflected, and not very thin : inner lip thickened in 

 full-grown specimens, and a little detached from the pillar ; 

 there is no chink behind it, much less an umbilicus : operculum 

 thin, yellowish, marked with slight flexuous stria3 in the line 

 of growth. L. 0-175. B. 0-06. 



Habitat : Muddy shores near high-water mark, under 

 stones, at Southampton, and at Salcombe, Plymouth, and 

 in other parts of South Devon (Montagu) ; Weymouth 

 (Bryer and others) ; Poole (Maton and Rackett) ; New- 

 haven (J. G. J.) ; Guernsey (Lukis) . It is rather 

 plentiful in the backwater behind Portland Island. 



* Having a small truncation. 



