'208 PNEUMONOBRANCHIATA. 



On the trunks of trees, under the bark, and im- 

 bedded in the lichen ; also in the fissures of rocks. 



Animal brownish yellow ; neck black ; foot grey, 

 granular, spotted, narrow, and elongate; tentacles, 

 upper thick, short, clavate ; lower scarcely visible, 

 very small, tubercular ; muzzle very blunt and large. 



Shell about a quarter of an inch long, slender, and 

 tapering to a rather sharp point, transparent yellow- 

 ish horn-colour, slightly striate longitudinally ; spire 

 consisting of from six to nine raised and well-defined 

 volutions ; aperture roundish-oval ; the peristome 

 thin, simple and a little reflected at the pillar so as 

 to form a slight umbilicus. In old and full-grown 

 shells there may be observed a slight fold or tooth 

 about the middle of the pillar, but which is seldom 

 to be met with. 



These shells vary considerably in their size, co- 

 lour, and shape, some being more ventricose than 

 others. Mr. Jeffreys, probably forgetting that these 

 animals are all hermaphrodite, observes, " The fe- 

 males have their shells much more ventricose and with 

 fewer volutions." (Linn. Trans, xvi. 351.) 



14. Clausilia. (Close Shell.) 



The animal like Bulimus, but the shell is reversed, 

 with an elongated, slender, fusiform spire, the 

 last volution less tumid than the one before it, with 

 an obtuse or papillary summit ; aperture oval, ob- 

 lique, united all round and margined, toothed; throat 

 furnished with an internal spiral shelly plait, or 

 clausium, fixed on an elastic pedicle, which closes 

 the cavity when the animal is withdrawn. 



The elegant spindle-shaped outline of this family 



