76 Dr Geo. Johnstone's Remarks on the class Mollusca 



to us alive, though in a languid state, and it continued so for 

 about twelve hours, yet it never discharged any inky fluid, 

 nor was the spirit in which it was preserved tinged in the slight- 

 est degree. 



In Avion and Limaxy the mouth is a short retractile proboscis, 

 armed on the upper lip with a semilunar horny plate, the conca- 

 vity turned downwards, and a blunt tooth projecting from its 

 centre. In the first genus, the margin of the shield is entire ; in 

 the latter, it is cleft below the pulmonary aperture. In giving 

 " black tentacula^' to Liviax agrestis, as a specific character, Dr 

 Fleming has incautiously copied his predecessors ; for, in truth, 

 they are not black, but like to the body in colour, as an exami- 

 nation of the first individual that crawls across his path will con- 

 vince him. We add a description of what we consider a new 

 species of Jrioii. 



1. A. CIRCUMSCEIPTUS. 



Body greyish-black, spotted, with a black fascia round the shield and body ; 

 the respiratory aperture anterior. 



Limax affrestis ? Latham, Lin. Trans, iv. 85. t. 8. f. 1, 4. — L. marginatus?^ 

 Muller, Verm. ii. 10. 



Hah. — Moist meadows, hedge-banks, &c. — Common. 



Desc. — Body 1 or 1 1 inch long, not keeled, nor much narrowed at the tail ; 

 greyish black, marbled, with a narrow fascia surrounding the back and shield ; 

 sides bluish-grey ; foot white, opaque ; tentacula rather short, black ; respira- 

 tory aperture placed very forward on the shield, which is entire ; mucous pore 

 very distinct, above the tail ; the young are white or straw-coloured, with 

 blackish head and tentacula. — This species has probably been passed over as a 

 variety of Limax agrestic. We have found it very uniform and constant in its 

 character, though it may possibly be the Ar. ater in an immature state. 



In the genus Helix, we find two species which Lamarck has, 

 perhaps with greater propriety, placed in the genus Carocolla. 

 These are the H. albella and elegans of Draparnaud. The H. 

 nitida and nitidula of the last author, and the H, alliaria of 

 Mr Miller are brought together as synonymous ; and, in confir- 

 mation of this arrangement, we may mention an experiment 

 which we lately made. Four specimens of equal size, and alike 

 in colour, and in the number of their whorls, were taken from 

 beneath one stone. None of them had any smell while alive ; 

 but, on immersing them, one by one, in hot water, two emitted 



