XXXVl 



ciii ercus ?ind agre/iis, Gmelin p. 3100, and p. 3101,"* 

 appear to be the link between the teflacea and monufca, 

 (being pofiTeffed of a flielly fubftance under the fhield 

 upon the back,) connefting thefe land animals together ; 

 as fome of the marine BuUce do that of the aquatic : 

 Bulla aperta, haliotoidea, diwA plumula, c<\\\di\\y conceal 

 their fhells. 



The circumftance of fome of the naked Limaces pof- 

 felTmg a fhell internally, the anatomical enquiries of 

 SwAMMERDAM and Lister could not overlook; both 

 thefe authors have dcfcribed and figured it.f 



That thefe animals therefore belong as much to the 

 Vervics teflacea as manv of the Bulla, there is no doubt ; 

 but it was not thought necelFary at prefent to form a new 

 genus on purpofe, for a flaapelefs fliell of irregular 

 growth. 



It is ufually fomewhat oval, fometimes flat and thin, 

 with a membranaceous margin ; others are half as thick 

 as they are bi'oad, and rarely poffeffcd of any concavity : 

 colour filvery-white, or of a micaceous appearance; the 

 upper fide is a little convex, and (lightly wrinkled con- 

 centrically to the fmaller, or pofterior, end: the under 



part 



* Llmax ftlans. Lin. Trans, iv. p. 85. tab 8. Both thefe Limaces are capable 

 of fufpenfion, as well as others which are deftitutc of fimilar hittmal confor- 

 mation. Limax parvus clncri-tis. LiJIer Conch. X. loi. f lOi. — ///. x.anat. f 5. 



t Hill. SivajnmerJ. p. 71, ■•.8. f. 8. — L'Jl. Conch, t. 5. aruil. f. 5. — hi. 

 An^l. p. 128. t. 2,f. 15. 



