80 COLIMACEA. 



it locates at Ballantrae, Ayrshire. Mr. Thompson informs us 

 that it is " indigenous to the more northern two-thirds of Ire- 

 land, from east to west." He particularises the Counties of 

 Down, Antrim, Clare, and Queen's County. 



It diflFers from the following species, in being more depressed 

 and transparent. 



30. Helix umbilicata, pi. VIII, f. 27, 28. 



Helix umbilicata, Montagu, Test. Brit., p. 434, pi. 13, f. 2 ; 

 Maton and Rackett, Linn. Tr., VIII, p. 20; Fleming, Brit. 

 An., p. 262; lb., Ency. Brit., VII, p. 80 ; Brown, EnCy. Brit., 

 6th Ed., VI, p. 458 ; lb., Wernerian Mem., II, p. 525 ; Tur- 

 ton, Brit. Fau., p. 189; Thompson, Ann. and Mag. Nat. Hist., 

 VI, p. 31 ; Helix rupestris, Drapernaud, p. 82, pi. 8, f. 7, 8, 9; 

 Ferussac, Prod., No. 201, pi. 80, f. 2, 3 ; Pfeiffer, III, p. 22, 

 pi. 4, f. 22 ; Turton, Man., p. 60, f. 45 ; Forbes, Mai. Mon., p. 

 8; Alder, Mag. Zool. and Bot., II, p. 109, No. 30; Zonites 

 rupestris, Leach, Moll., p. 103; Helix umbilicata, Brown, 

 Illust. Conch., p. 51, pi. 17, f. 30, 31 ; lb., First Ed., pi. 40, f. 

 30, 31. 



Shell subpellucid, of a dark burnt umber-brown colour; body 

 large ; spire of medium length, consisting of four much inflated 

 volutions, deeply divided by the sutural line, and terminating in 

 a moderately produced apex; whole shell covered by very fine, 

 longitudinal striae ; aperture nearly circular ; outer lip thin, and 

 not reflected ; base rounded and inflated, with a very large and 

 deep umbilicus, exposing the inside of the volutions of the 

 spire. Diameter at the base one-tenth of an inch ; height not 

 quite so much. 



This shell has much the aspect of the preceding, but will be 

 readily recognised by its superior size, being a third larger than 

 that of the latter. It is rather local in Britain. It frequents 

 high rocky situations, lurking in crevices, of dry and old walls, 

 and under stones. Montagu says, "it is remarkable that this 

 shell always affects such lofty places as the tops of houses, with- 

 out one being found near the base ; and in that situation its 

 inhabitant braves equally the scorching beams of the sun in 

 summer, and the frigid winds of winter, without attempting to 

 descend." Thompson remarks that it is generally distributed 

 throughout the southern three-fourths of Ireland, more parti- 



