ACADEMY OF NATURAL SCIENCES. 217 



Genus Isapis, H. & A. Adams. 



Isapis obtusa, Cpr. u. s. State Collection, No. 682. 



I. t. " I. fenestrates" indole simili, sed magis elongata, subnitente. pallide rosa- 

 cea ; vertice nucleoso decliviter immerso, celato ; anfr. norm, postice subplanatis, 

 suturis obtusis ; costis tumentibus rotundatis circ. vii., suturas et urnbilicum 

 minorem versus obsoletis, plus miuusve extantibus ; interstitiis parvis, irregular- 

 ibus, haud decussatis ; peritremati continuo, labro tenui, secundum costas vari- 

 antes undulato ; labio medio calloso. 



Long. 0-23, long. spir. 0-09, lat. 0-16, div. 60°. 



Hab. S. Diego, 10 fm. ; Sta. Barbara, 20 fin. ; Cooper. 



The fortunate discovery of some perfect young specimens displays a nucleus 

 so like Odostomia that, despite the resemblance of the shell to Fossarus, which 

 has a tuberoid nucleus, it most probably belongs to Pyramidellidce. 



Genus Rissoina, D'Orbiguy. 

 Rissoina interfossa, Cpr. n. s. State Collection, No. 387, b. 



R. t. satis magna, crassa, alba, satis turrita, conspicue sculpta ; marginibus 

 spiraa rectis, vertice mamillato ; anfr. nucl. ? . . [detritis] ; norm. vii. tumidis, 

 angulatis, suturis angulatim impressis ; carinis spiralibus validis, in spira ii. ; 

 altera postica interdum intercalate ; anfr. ultimo duabus quoque peripheriali- 

 bus, quinta axim circumeunte* ; costis radiantibus validis, extantibus, circ. xiv., 

 ad suturas contiguis, liris regularibus spiram ascendentibus, ad intersectiones 

 carinarum nodulosis, ad peripheriam continuis ; interstitiis quadratis, alte infos- 

 satis ; apertura ovata. 



Long. 0-26, long. spir. 0-18, lat. 040 ; div. 28°. 



Hab. Catalina Is. 8-10 fm. 4 ; San Diego 1 ; Monterey, (var.) Cooper. 



Genus Rissoa, Freminville. 

 Rissoa acutelirata, Cpr. n. s. 



R. t. tenui, satis turrita, rufocinerea, marginibus spira? parum excurvatis ; 

 anfr. nucl. iii. normalibus lrcvibus, vertice parum mamillato ; norm. iii. subro- 

 tundatis, suturis valde impressis ; liris radiantibus circ. xviii. acutis, distantibus, 

 ad peripheriam evanidis ; lirulis acutis spiralibus distantibus circ. xv., quarnni 

 vi. in spira monstrantur, liris radiantibus et interstitiis latis, undatis, eleganter 

 superantibus, haud nodulosis ; basi rotundata, haud umbilicata ; apertura ovata, 

 peritremati continuo. 



Long. 0-09, long. spir. 0-05, lat. 0-05, div. 35°. 



Hab. S. Diego ; 1 sp. and fragment in shell-washings. Cooper. 



Genus Fenella, H. & A. Adams. 



Fenella pupoidea, Cpr. n. s. State Collection, No. 389. 



F. t. Truncatellceformi, sed apice haud decollate ; colore maxime variante ; 

 seu unicolori, albido, cinereo, viridescente, rufofusco, seu splendide rubro ; seu 

 varie fusco maculato ; anfr. nucl. iii. lasvibus, globosis, vertice mamillato ; norm. 



