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20 Mr. A. Adams on new Mollusca from Japan. 



IV. — Mollusca Japonica : New Species of Odostomia. 

 By Arthur Adams, F.L.S., &c. 



The genus Odostomia, as at present constituted, comprises a 

 very incongruous assemblage. Many species appear to belong 

 to Parthenia, such as O. terebellum and O. Humboldtii, Phil. O. 

 Achates, Gould, is an Obeliscus, as is also, I believe, O. lamellata, 

 Carp. The British forms also require supervision ; and this is the 

 more necessary in a family where the species are already so 

 numerous and of such small dimensions. In the work by my 

 brother and myself, which is merely a rough sketch of the mol- 

 luscous subkingdom, every genus of small shells could not be 

 minutely analysed ; but when complete monographs of all the 

 genera shall have been made by competent persons, some degree of 

 exactness will be given to the smaller divisions, and the study of 

 species be thus facilitated. In the meantime, I offer descriptions 

 of fourteen species of true Odostomice from a sea whence not a 

 single species has hitherto been obtained by naturalists. 



1. Odostomia oblonga, A. Adams. 



O. testa ovoidea, utrinque acuminata, alba, solida, imperforata ; an- 

 fractibus normalibus 4, planatis, ultimo magno ovato ; apertura 

 oblonga, antice producta et acuminata; plica parietali obliqua, 

 valida ; labro arcuato, subincrassato. 



Hab. Korea Strait, near Mino-Sima ; 63 fathoms. 



2. Odostomia hyalina, A. Adams. 



O. testa ovato-conica, tenui, subdiaphana, alba ; anfractibus norma- 

 libus 5, planulatis, ultimo ad peripheriam subangulato; snturis 

 acute exaratis ; apertura oblongo-ovali, antice subproducta ; plica 

 parietali transversa, valida ; labro in medio subangulato. 



Hab. Mino-Sima ; 63 fathoms. 



3. Odostomia elata, A. Adams. 



O. testa elongato-conica, spira acuminata, alba, nitida, solida ; an- 

 fractibus normalibus 5, planatis ; suturis exaratis ; anfractu ultimo 

 ad peripheriam subangulato ; apertura ovata ; plica parietali 

 obliqua ; labro in medio subangulato. 



Hab. Mino-Sima; 63 fathoms. 



4. Odostomia scalina, A. Adams. 



O. testa elongato-conoidea, subturrita, spira elata, alba, rimata, 

 tenui ; anfractibus normalibus 5, convexis, ultimo rotundato ; 

 suturis impressis ; apertura oblonga ; plica parietali parva, trans- 

 versa ; labro simplici, acuto. 



Hab. Mino-Sima ; 60 fathoms. 



