ODOSTOMIA. 107 



or suboval, with a narrow border of pale bistre with a pinkish 

 hue ; the stria? of increment radiate as in most of the other 

 Chemnitzke" (Clark)]. L. 0-065. B. 0-025. 



Var. tenuicula. Comparatively diminutive, and more slender. 



Habitat : Coralline zone in Shetland and Skye (Bar- 

 lee and J. G. J.) ; off Larue, co. Antrim (Hyndman and 

 J. G. J.); Falmouth (Barlee and Hockin); Helford 

 (Hockin) ; Fowey (Barlee) ; Exmouth (Clark and Bar- 

 lee); Weymouth and Sandwich (J. G. J.); and Guern- 

 sey (Barlee and J. G. J.). The variety, which may be 

 the male, is from Lamlash Bay (Bean) ; L. Strangford 

 (Waller); Land's End (Hockin); and Guernsey (J. G. J.). 

 A. Gulsonce has been found by Mr. S. Wood in the 

 Coralline Crag at Clacton, and dredged in Vigo Bay by 

 Mr. M 'Andrew. It is rare. 



Mr. Clark noticed that the animal seldom protrudes its 

 eyes and tentacles. He mentions " a rudimental denticle 

 on the pillar-lip." I have minutely examined more than 

 20 specimens, but could not detect any such process. 



This and A. unica are aberrant forms of Aclis. Each 

 has peculiar characters, which render their systematic 

 allocation very difficult. Having suggested another 

 generic name for A. unica, in the event of its being 

 considered necessary to separate it from the present 

 genus, I would also venture in the like contingency to 

 propose the generic name of Menippe for A. Gulsonce. 



Genus II. ODOSTO'MIA * Fleming. PI. II. f. 5. 



Body usually slender : mantle plain-edged, somewhat folded 

 on the right, so as to form a slight canal: snout (or head- 

 flap) projecting beyond the foot : proboscis long, issuing from 

 a slit just below the space in front between the tentacles ; it 



* Mouth of the shell furnished with a tooth ; per syncopen for Odon- 

 tostomia. 



