BY K. M. JOHNSTON, F.L.S. 



65 



Ostreidae, ci. 



Shell inequivalve, upper one flat, no teeth 

 Shell thin, perlaceous, with a deep notch 



or hole in the inferior valve, 



attached 

 Shell eared,sub-orbicular,radiately ribbed 

 Shell eared, white, gaping at the sides, 



equivalve often minute 



(O.J Shell globular, three lobed, concen- 

 trically striated, open in front and 

 behind, lodged at the extremity of a 

 shelly lined tube or burrow 



Class BEACHIOPODA. 

 (D.) Shell roundoroval, perforated near 



or at the apex, minutely punctate Terebratulidse, cii. 



Anonnidaa, c. 

 Pectinidae, xcviii. 



Limidse, xcix. 



Tercdidas, lxx. 



Limacidffie, Ixi. 



Arionidse, lxii. 



(III.) LAND AND FEESH WATEE MOLLUSCS. 



(A.J Land Slugs, or Snails ; shell none, or 

 Shell rudimentary, a calcareous plate 



concealed under the mantle, jaw 



of animal without ribs 

 Shell rudimentary, often composed of a 



few calcareous grains, jaw of 



animal strongly ribbed 

 (2.) Land Snails, with shell more or less spiral and fully 

 developed. 

 "hell small,oval,with short spire, fragile, 



whorls few, rapidly enlarging, 



resembling some fresh water 



Lymnma 

 knell usually thin, corneous, transparent, 



plaits spiral, of few rapidly en- 

 larging whorls, animal too large 



to entirely enter 

 of variable form, large or very 



minute, smooth, rugose, striated 



ribbed or cancellate, sometimes 



pilose, orbicular planoid convex, 



planorboid trochiform (Helix 



Launcestonensis) s ub-turriculated 



or short — Helix — shell large, 



oblong, spiral (Bulimus) 



minute, multispiral, cylindrical, 



with obtuse summit, pupiform, 



aperture small, usually contracted 



oy internal teeth or lamellae. 



Whorls reversed in local example Pupidae, lx. 



Shell 



Succineidse, lxiii. 



Vitrinidse, lviii. 



Shell 



Helicidse, lix. 



