186 



from it. Its principal distinctions are, a more elevated pyramid, 

 more rounded whorls, less oblique aperture, destitution of undulations 

 on the surface, with generally, revolving cords, more defined and 

 brighter coloration, lip rounded and nacreous, instead of sharp and 

 black. Santa Barbara. Col. Jewett. 



Trochus (Monodonta) pyriformis [is Osilinus gallina Forbes, 

 variety]. 



Modulus dorsuosus. T. depressa, ovato-conica, solida, calcarea, 

 ad peripheriam acuta et nodulosa, supra obscure undulato-nodosa, 

 infra conica, spiraliter insculpta: apertura sub-triangularis, labro 

 acuto intus sulcato ; columella et dente rosaceis ; umbilico parvo, pro- 

 fundo. Diameter half an inch ; axis one third of an inch. Found at 

 Acapulco. Col. Jewett. 



Approaches M. duplicatus, which is described as spirally grooved 

 above. 



Chemnitzia tenuicula. T. gracillima, lanceolata, nitida, cerina 

 infra suturam rufescens; anfr. 10 planulatis, tabulatis, longitudinaliter 

 ad 20-plicatis ; striis numerosis volventibus leviter secatis ; basi modo 

 spiraliter striata : apertura angusta ovata ; labro acuto. Axis 0.3 ; 

 diam. 0.05 poll. Inhabits Santa Barbara. Col. Jewett. 



May be compared with C. formosa, but is less accurately acicular, 

 the posterior whorls increasing more rapidly than the others. 



Chemnitzia torquata. T. solida, turrita, lactea; anfr. 8 eon- 

 vexiusculis, plicis longitudinalibus flexuosis perobliquis ad 1 6 ornatis ; 

 anfractu ultimo subangulato ; basi inornata : apertura subovata ; 

 labro incrassato. Long. 0.2; lat. 0.05 poll. Obtained at Santa Bar- 

 bara. Col. Jewett. 



Formed much like C. clatlirata, but is smaller, has no revolving lines, 

 and the folds are more oblique. 



Odostomia gravida. T. ovato-conica, elevata, eburnea, polita ; 

 spira acuta ; anfr. 6 supra rotundatis, idtimo subangulato § testa? ade- 

 quante : apertura ovata, antice rotundata, postice acuta ; labro ex- 

 panse ; plica columellari acuta, transversa, umbilico parvo suffossa. 

 Axis \ ; diam. -jL poll. Inhabits Santa Barbara. Col. Jewett. 



Has most of the characters of O. conoidea of Europe, but is propor- 

 tionally broader. 



Odostomia achates. T. ovato-lanceolata, nitida, longitudinaliter 

 striata, albida, maculis elongatis rubiginosis obscure zonata; spira 

 acuta, anfr. ad vix convexis, ultimo dimidiam longitud. testa? ade- 

 quante, basi rotundata et stria unica submediana cincta : apertura 

 angusta, ovata, postice acuta; columella plica mediana et duabus 

 minoribus anterioribus instructa. Long. £ ; lat. ■£$ poll. Inhabits 

 Mazatlan. Col. Jewett. 



