Moliuslis. 5101 



aerated, the auricle and ventricle are placed longitudinally, the latter 

 being anterior. 



Shell external, very small, solid, auriform, depressed and slightly 

 spiral at the apex, having a very large and oval aperture ; the right 

 lip simple and trenchant, the left convex, sharp and reflected ; the 

 shell covers the posterior part of the pulmonary cavity. 



The genus has in its form and size much resemblance to a small 

 slug, but is distinguished from it by the cloak, which is very exten- 

 sible, being placed far back on the body, contained in a very small 

 shell, and by two grooves which pass from the base of the tentacles 

 to Hie shell ; its branchial and anal apertures are also near the tail, 

 instead of, as in the slugs, being near the fore part. 



De Ferussac remarked that the simple gelatinous contractile 

 mantle of the animal, hidden habitually under the shell, is divided 

 into many lobes, capable of enveloping the whole body, by an extra- 

 ordinary development, when the animal finds it necessary to protect 

 itself from the consequences of too great dryness. The Encyclop. 

 Metrop. tit. " Testacella," probably alluding to the same fact as De 

 Ferussac, states that " during draught they are capable of distending 

 the cloak and almost enclosing the little shell." These words, 

 " little shell," must, I imagine, be an error. 



Species. 



The number of species given by Lamarck is one only ; M. De- 

 shayes, in his * Tables,' makes the number two (both recent) ; one only 

 is recorded in the last edition of Lamarck; Mr. G. B. Sowerby figures 

 and describes three. 



Special Characters. 



9 



T. haliotoideus, Faure Big net. 



Animal. — Flavidum rufum, vel griseum, maculatum aut immacttla- 

 tum ; tentaculis cylindricis. 



Testa. — Ovata, postice acuminata, cornea, crassa, extus rugosa, 

 intus nitida: clavicula (inner lip, G. B. Sowerby) alba lata et plaua. 

 (Loudon's Mag. Nat. Hist. vii. 229). 



The physiology of this species is treated at large by Cuvier, in his 

 Mejp. sur la Dolabelle, supra. •** 



Habitat. — South of France and Clifton. (Encyclop. Metrop. tit. 

 "Testacella.") La France, Cuv. par G. Meneville (Mollusques), 



