400 



November 21, 1860. 



The President in the Chair. 



Dr. A. A. Gould presented the following descriptions 

 of shells collected by the North Pacific Exploring Expe- 

 dition : 



Alaba puncto-striata. T. alba, hyalina, ubiqiie spiraliter 

 tenuissime striata, striis punctulatis ; anfr. 4 convexiusculis, posti- 

 cis leevibus, viridioribus, alteris plerumque tervaricosis, varicibus 

 rotundatis niveis : apertura ovata, antice parum effusa ; labro 

 acuto; columella aurantiaco tincta. Axis .18; diam. .07 poll. 

 Inhabits Loo Choo Is. W. S. 



The generic place of this beautifully transparent and delicately 

 sculptured shell is somewhat doubtful. 



RissoiNA TROCHLEARis. T. parva, crassa, cinerea, ovoidea ; 

 anfr. nucleosis tribus levibus, normalibus 4 convexiusculis, ultimo 

 carinis 7 elevatis acutis cincto, quarum 2-4 (plerumque 3) spiram 

 ascendunt; interstitiis late excavatis, stepe clathratis : apertura 

 ovalis; peritremate continuo vel in juniorem effuso. Axis .16; 

 diam. .073 poll. Inhabits China Seas. W. S. 



Resembles Parthenia exarata ; and possibly may be a Rissoa. 



RissoiNA IMBRICATA. T. ovato-lanccolata, porcellana, nitida ; 

 anfr. 8 planulatis, tabulatis, liris imbricantibus numerosis cinctis : 

 apertura ovata, effusa ; peritremate expanso, simplici ; columella 

 torta. Axis 7 ; diam. 3 millim. Inhabits China Seas. W. S. 



RissoiNA FLEXUOSA. T. fusiformis, turrita, straminea ; anfr. 

 7 convexiusculis, plicis obtusis flexuosis circ. 15 clathratis, et 

 lineis volventibus numerosis cinctis : apertura satis magna, semi- 

 circularis ; peritremate simplici, expanso, antice etfuso. Axis 6 ; 

 diam. 2 milUm. Inhabits Sydney Harbor. W. S. 



RissoiNA NiTiDULA. T. acicularis, vitrea, nitida ; anfr. 9 ad 

 suturam profunde declivibus, plicis inconspicuis ad 18 et fills vol- 

 ventibus circ. 4 insculptis : apertura ovata, vix effusa ; peritre- 

 mate acuto, fills crenato. Axis 5 ; diam. 2 millim. Inhabits 

 Cliina Seas. W. S. 



