ODOSTOMIA. 145 



the mouth upwards, and at least two-thirds of it when viewed 

 in an opposite position : suture channelled, rather oblique : 

 mouth roundish-oval, not contracted above, slightly expanded 

 below ; it considerably exceeds in length one-half of the whole 

 spire : outer Up abruptly incurved on the periphery : inner lip 

 thin on the upper part (where it is united with the outer lip), 

 broad, thickened, a little reflected, almost straight, and shel- 

 ving outwards on the lower part, which is more than thrice as 

 long as the other : umbilicus consisting of a narrow, although 

 distinct, depression, which terminates in a small chink : tooth 

 strong, conspicuous, hke a short thorn, projecting from the 

 middle of the inner or pillar-lip : operculum, according to Mr. 

 Clark, cartilaginous and flexible, with the strife of growth ar- 

 ranged in elliptical curves, as in 0. pallida. L. 0-075. 

 B. 0-05. 



Habitat : Aberdeenshire (Daw^son) ; Hebrides (Bar- 

 lee) ; Scarborough (Bean and J. G. J.) ; Barmouth^ 

 Tenby^ Swansea, Sandwich, Paington, and Guernsey 

 (J. G. J.) ; littoral zone, Exmouth (Clark) ; Burro^v 

 Island (Barlee) ; Hayle and Land^s End (Hockin) . 

 Local and rare. M. Tasle has found this species at 

 Morbihan in Brittany ; and I dredged it in the Gulf of 

 Spezzia. 



It is impossible to determine Walker^s shell, fig. 55, 

 which Montagu named Turbo Sandvicensis. The cha- 

 racteristic word ^'^ reticulatis,^' used by Walker in his 

 short diagnosis, with reference to the whorls, is appli- 

 cable to 0. decussata, but not to the shell which I have 

 now described ; if the figure were the sole criterion, I 

 should be disposed to assign it to the present species. 



20. O. decussa'ta"^, Montagu. 



Turbo decussatus, Mont. Test. Br. (ii.) p. 322, t. 12. f. 4. 0. decussafa, 

 F. & H. iii. p. 303, pi. xcvii. f. 6, 7. 



Body clear white, except the head, which is pale-pink or 

 red : snout small, somewhat cylindrical, narrow, and attenuated 



* Divided crosswise. 

 VOL. IV. H 



