from the West Coast of North America. 181 



329 6. Bittium (?var.) esuriens. 



B. testa B. filoso simili, sed multo minore, graciliore, interdum valde 

 attenuata ; sculptura testae jun. ut in B. filoso, testae adultse sub- 

 obsoleta; interstitiis hand insculptis. Long. '3, long. spir. "21, 

 lat. -11, div. 25°. 

 Hab. Sta. Barbara (Jewett) ; Neeah Bay (Swan) ; Monterey 



(Cooper). 



334. Bittium fastigiatum. 



B. testa parva, gracili, pallide rufo-cinerea, marginibus spirae vix 

 excurvatis ; anfr. nucl. iii., laevibus, tumidis, apice acuto; norm, ix., 

 planatis, suturis alte impressis ; anfr. primis iii. carinatis, postea 

 costis radiantibus circ. xiii., obtusis, satis extantibus, ad suturas 

 interruptis, interstitiis undatis, liris spiralibus iv. in spira se mon- 

 strantibus, costas undatim superantibus, quarum antica in testa 

 jun. plerumque extat; anfr. ultimo parum contracto, basi elongata, 

 liris spiralibus vi. contiguis ornata ; apertura gibbosa ; labro 

 acuto, interdum varicoso, antice angulatim emarginato ; labio 

 tenui. Long. -25, long. spir. '19, lat. *09, div. 20°. 



Hab. Sta. Barbara (Jewett). 



Genus Amphithalamus*. 



Testa Rissoidea, nucleo magno ; apertura labio producto, labro 

 subpostice juncto, subito in adulta contracto. 



355. Amphithalamus inclusus. 



A. testa minuta, lata, solidiore, pallide rufo-fusca; vertice mamillato; 

 anfr. nucl. uno et dimidio, quoad magnitudinem permagnis, mi- 

 nutissime et confertissime spiraliter et radiatim striolatis ; anfr. 

 norm, iii., laevibus, subplanatis, suturis impressis ; basi subangulata ; 

 costa peripherica rotundata, haud extante, interdum in spira se 

 monstrante ; costa altera circa regionem pseudo-umbilicarem ; labro 

 acuto, haud contracto : labio testa adolescente normali, dein a 

 pariete separata, sinum posticum suturam versus formante, t. adulta 

 valde separata, regionem quasi umbilicarem magnam formante; ad 

 labrum subito fere perpendiculariter, subpostice juncto : operculo 

 tenuissimo. Long. '04, long. spir. *02, lat. -03, div. 60°. 



Hab. Sta. Barbara (Jewett); S. Diego (Cooper). 



This very remarkable little shell bears the same relation to 

 Rissoa that Stoastoma does to Helicina. The peritreme resem- 

 bles a figure fa inverted, as on the face of the type. In the dis- 

 proportionate size of the nuclear whorls it resembles Vitrinella. 



373. Drillia mcesta. 



D. testa acuminata, lsevi, dense olivaceo-fusca, epidermide laevi ad- 

 hserente induta ; anfr. nucleosis 1 . . . (decollatis) ; norm, viii., parum 



* Th. dfixf>\, ddXnfios, having a chamber on both sides. 



