MOLLUSCA. 481 



to occasion the loss of the hair ; while the sight of it would 

 not fail to subdue the obstinacy of concealed pregnancy. 

 The progress of science has exposed the errors, or perhaps 

 tricks, of the earlier observers, and proved the innocence of 

 an animal formerly invested with every repulsive and 

 noxious attribute. The A. depilanSy the type of the 

 genus, is of frequent occurrence on the British shores. 

 The A. punctata of Cuvier may be regarded merely as a 

 variety *. 



47. NoTARCHUs. Lid of the branchiae soft. 



There is an oblique groove from the neck leading to the 

 branchias. The structure is similar to Aplysia. M. Cu- 

 vier instituted this genus in his Regne Animal, vol. ii. 

 p. 395, and vol. iv. tab. xi. f 1. 



b. Branchiae terminal. 



48. DoLABELLA. Dorsal plate a solid shell. 



* It is probably at this place where the genus Gasteroplax of Blainville, 

 published by Lamarck, under the ill-judged title Umbrella {Hist. Nat. ^c. 

 vol. vi. p. 339), should be introduced. The following is the extended cha- 

 racter which has been communicated : 



" Corpus valde crassum, obovatum, testa dorsali onustum ; pede amplis- 

 simo, subtus piano, undique prominente, anterius sinu emarginato, postice 

 attenuate. Caput non distinctum. Cavitas infundibuliformis in sinu antico 

 pedis OS in fundo recondens. Tentaculo quatuor ; superiora duo, crassa, 

 brevia, truncata, hinc fissa, intus transversim sublamellosa ; altera duo, te- 

 nuia, cristata, pedicellata, ad oris latera. Branchiee foliaceae, serratim ordi- 

 natas, infra cutis marginem per totam longitudinem lateris dextri. Anus post 

 extremitatem posticam branchiarum. 



Testa externa, orbicularis, subirregularis, planulata, superne convexius- 

 cula, albida, versus medium mucrone, apicicali brevissimo pra^bita ; mar- 

 ginibus acutis : interna facie subconcava ; disco calloso, colorato, ad centrum 

 impresso, limbo laevi cincto." 



Doubts seem to be entertained whether the shell is to be considered as be=. 

 longing to the cloak or the foot. Two species are known. 



VOL. II. H h 



