Mr. A. Adams on new Mollusca from Japan. 405 



and having since then belonged to several owners. I have, 

 however, learned that one of her latest voyages was to Matamoras. 



Every shell was not only empty, but was perfectly cleaned out; 

 from which I infer that, after the vessel came into the colder 

 waters of the temperate zone, the oysters died, and, their shells 

 consequently opening, they were speedily devoured by Crusta- 

 ceans and other carnivorous creatures. Owing to this circum- 

 stance, by far the larger proportion of the oysters wanted their 

 upper valves, which had dropped off, the hinge not being able 

 to sustain the weight of the valve, which, from the oysters' posi- 

 tion on the ship, would hang downwards. 



Description of the Shell. Attached by its lower valve, which 

 varies in shape according to the extent of the attachment : when 

 only slightly adherent, it is very concave. The upper valve flat, 

 or slightly concave, and foliaceous. In some specimens there are 

 well-marked plaits on the outer surface. The nacreous lining of 

 the upper valve is white ; that of the lower one is of a deep rich 

 copper-brown colour in the middle, with a margin of white. 

 The hinge toothless, with a laminated subnacreous structure. 



I send you herewith specimens ; and if you think that they 

 possess any value, I shall be obliged by your making known to 

 your readers that, to the extent of my stock, I shall be glad to 

 give them to public museums and important private collections. 



XLV. On some New Genera and Species of Mollusca from 

 Japan. BY ARTHUR ADAMS, F.L.S., &c. 



[Continued from p. 303.] 

 Genus SYRNOLA, A. Adams. 



Testa subulata, recta, vitrea, polita ; anfractibus planis ; suturis im- 

 pressis. Apertura oblonga ; lahio in medio plica obliqua instructo ; 

 labro simplici, acuto. 



This genus bears the same relation to Obeliscus that Chrysallida 

 does to Pyramidella, and will include all the slender species 

 of the former group with a single plait on the columella. It 

 differs from Monoptygma in being vitreous and polished, and 

 from Odostomia in texture and its subulate or aciculate form. 



Syrnola gracillima, A. Adams. 



S. testa subulata, alba, vitrea, subopaca ; anfractibus novem, leevibus, 

 planulatis, suturis valde impressis, anfractu ultimo linea rufo-fusca 

 angusta circumcincto, antice rotundato ; labio antice expanse et 

 rerlexo, in medio plica obliqua valida instructo j labro intus sub- 

 incrassato. 



Hab. Straits of Korea; 63 fathoms. 



