COLIMACEA. 87 



3y. Helix obvoluta, pi. IX, f. 16, 17. 



Helix obvoluta, Miiller, Venn., II, p. 24 ; Helix holosericea, 

 Drapernaufl, p. 112, pi. 7, f. 27 and 29 ; Brard, p. 62, pi. 2, f. 

 16, 17; Pfeiffer, I, p. 41, pi. 2, f. 28 ; Rossmassler, I, p. 70, 

 pi. 1, f. 21 ; Ferussac, Prod., p. 38, No. 107; Lindsay, Linn. 

 Trans., XVI, p. 765; Helix obvoluta, Brown, Illust. Conch., p. 



53, pi. 18,* f. 13, 14. 



Shell reddish-brown, planorbiform, depressed both above and 

 below, and largely umbilicated; spire concave, and consisting of 

 five narrow volutions ; aperture triangular ; the outer lip re- 

 flexed, pale red, and provided internally with a small, blunted 

 tooth. Diameter five-eighths of an inch. 



Discovered by Dr. James Lindsay in Ditcham Wood, near 

 Brenton, Hampshire, where he collected about twenty speci- 

 mens. Its habitat is among moss at the roots of trees. As 

 this shell is a well knovvn continental species, and having been 

 found in one locality only, it is probable that it has been intro- 

 duced among plants. 



40. Helix margaritacea, pi. IX, f. 18, 19? 20. 



Helix margaritacea, Brown, Illust. Conch., p. 54, pi. 17, f. 



54, 55, 56 ; Vitrina margaritacea, Brown, First Ed., pi. 40, f. 

 54, 55, 56. 



Shell depressed both above and below, very thin and hyaline; 

 spire hardly elevated above the body, and consisting of three 

 pretty well rounded and rapidly decreasing volutions ; sides of 

 the body inflated, and rather thick in proportion to its size ; 

 base rounded, and provided with a small and shallow umbilicus; 

 aperture suborbicular, with a very thin outer lip; whole surface 

 of a pearly white, exhibiting iridescent reflections. Diameter 

 an eighth of an inch. 



Discovered by James Gerard, Esq., on an old wall at Cor- 

 storphine Hill, near Edinburgh. 



ORDER GASTEROPODA. 



Animals with straight bodies, never spiral, nor totally en- 

 veloped in their shell ; the foot, or disc, situated under the 

 belly, united to the body nearly its whole length, and serving 

 as an organ of locomotion. 



