348 Mr. A. Adams on Microstelma and Onoba, 



from its shell ; and I may here take the opportunity of stating 

 that the true position of the genus is in Anatinidse, and not 

 with Isocardia, with which, in a former communication, I had 

 associated it. My brother, in examining one of my fresh speci- 

 mens, has proved the existence of an ossicle in the hinge, very 

 similar to that in Chamostrea or Cleidotherus. 



Microstelma Dadala, A. Adams. 



M. testa ovata, rimata, solida, alba ; anfractibus 5g, planis, postice 

 angulatis et coronatis, longitudinaliter plicatis, plicis rectis, validis, 

 sequalibus, interstitiis transversim striatis ; anfractu ultimo magno, 

 plicis, ultra peripheriam, evanidis ; labro margine postice angu- 

 lato. 



Hab. Gotto Islands ; 48 fathoms. 



The whorls are very prettily coronate at the hind part, which 

 suggested the generic name. In all essentials the shell appears 

 to be of a Rissoid character, reminding one somewhat of Ris- 

 soina. Had there been any indication of columellar plaits, it 

 might have been mistaken for a Pyramidellid. 



Genus Onoba, H. & A. Adams. 



1. Onoba elegans, A. Adams. 

 Rissoa elegans, A.Adams, Proc. Zool. Soc. 1851. 



Hab. Seto-Uchi; 17 fathoms. Yara; 9 fathoms, mud. 



2. Onoba procera, A. Adams. 

 Onoba procera, A. Adams,\Ann. & Mag. Nat. Hist. 1861. 



Hab. Yara; 9 fathoms, mud. Mososeki; 7 fathoms. 



3. Onoba mirifica, A. Adams. 



O. testa subulato-turrita, alba, semipellucida ; anfractibus 5, con- 

 vexiusculis, suturis profundis, transversim liratis, liris validis, 

 subdistautibus, interstitiis concinne cancellatis ; anfractu ultimo 

 costa basali instructo ; apertura ovata, antice integra ; peristomate 

 continuo ; labro subdilatato, margine extus varicoso. 



Hab. Kino-O-Sima; Tanabe. 



A small shell, but exquisite in form and sculpture. 



4. Onoba bella, A. Adams. 

 Rissoa bella, A. Adams, Proc. Zool. Soc. 1851, p. 267. 

 Hab. Yara ; 9 fathoms, mud. 



5. Onoba spirata, A. Adams. 

 0. testa ovato-turrita, subrimata, tenui, sordide alba ; anfractibus 5, 



