ODOSTOMIA. 281 



much arcuated, and very narrowly reflected. The fold is 

 distinct, but not large ; it is situated at about one-third 

 the distance from the posterior corner of the aperture. 

 The axis is perforated by a very distinct umbilicus. The 

 length of the specimen, which is about twice its breadth, 

 is only the tenth of an inch. It was taken in sand from 

 Tynemouth (Alder). Torquay and the west of Scotland 

 are mentioned as additional localities by Mr. Jeffreys. 



Mr. Clark has forwarded us the following account of an 

 animal which he doubtfully refers to the present species. 

 The shell, though closely connected and probably a variety, 

 differs in some respects from the type, the extreme tumidity 

 of whose volutions may possibly be accidental ; we have 

 consequently given a brief description of it below.* 



" Animal with the mantle not produced beyond the mar- 

 gin of the shell. Head short, flat, not grooved nor cloven, 

 gently arcuated at its terminus ; it issues between the foot 

 and tentacular veil, and with the tentacula extends a little 

 beyond the foot. The veil is entire, with a sweeping 

 indentation, which resolves itself at the right and left 

 angles, into two very short broad awl-shaped bevelled 

 blunt tentacula, on each of which there is an opaque linear 

 stripe from base to point. They are hyaline, setaceous, 

 with the tops marked with a round opake white dot, which 



* Shell (Plate XCIV. f. 7) of a somewhat conoid ovate or subovate shape, 

 being quickly attenuated above to a small blunt apex ; very thin, subperfo- 

 rated, transparent, shining, white or yellowish white, smooth or nearly so. 

 Whorls much tapering, of very quick longitudinal increase, more or less vcntri- 

 cose, deeply divided. Body large, occupying half the entire length, well rounded, 

 but rather gradually declining below. Nucleus not very oblique. Mouth rather 

 capacious, somewhat ovate or rounded ovate, equal in length to the four turns 

 above it, sometimes a little disposed to expand anteriorly. Outer lip arched 

 throughout, smooth witliin. Inner lip arcuated and peculiarly elongated ; its 

 reflection narrow, and not appressed; the fold extremely small and somewhat 

 retired. Length scarcely a line. 



VOL. III. O O 



