from the West Coast of North America. 5 



3296. Bittium (?var.) esuriens. 



B. testa B. filoso sirnili, sed multo minore, graciliore, interdum vald. 

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

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

 lat. -11, div. 25. 



Hob. 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., Isevibus, tumidis, apice acuto; nqpm. ix., 

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

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

 interrupts, interstitiis undatis, liris spiralibus iv. in spira se mori- 

 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. *U9, div. 20. 



Hob. Sta. Barbara (Jewett}. 



Genus AMPHITHALAMUS*. 



Testa Rissoidea, nucleo magno ; apertura labio producto, labro 

 subpostice juricto, subito in adulta contracto. 



355. Amphithalamus inclusus. 



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

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

 nutissime et confertissime spiraliter et radiatim striolatis ; anfr. 

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

 costa peripherica rotundata, baud extante, interdum in spira se 

 monstrante; costa altera circa regionem pseudo-umbilicarem ; labro 

 acuto, baud 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 : operculr 

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



Hob. 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 5 inverted, as on the face of the type. In the dis- 

 proportionate size of the nuclear whorls it resembles Vitrinella. 



373. Drillia mast a. 



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

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



* Th. dfj.(f>\, 8d\ap,os, having a chamber on both sides. 



283 



