480 Zoological Society. 



Hab. Sitka, North-west America. Dredged in the harbour from 

 a sandy bottom, in from five to seven fathoms, together Mdth T. 

 inermis. 



Shell oblong, the spire more produced than in T. bicarinata ; the 

 whorls separated by a deep suture, profoundly cancellated ; many- 

 keeled, and furnished on the lines of the striae of increase with nu- 

 merous short bristles at regular intervals. The aperture is rounded, 

 and truncated at the base ; the canal so short as scarcely to exist. 

 Umbilicus small, and somewhat concealed by the inner lip, which is 

 slightly developed. 



Three specimens are in the collection, and one, being a dead shell 

 and deprived of its epidermis, shows very distinctly the deep cancel- 

 lation of the whorls. A single specimen, and larger by two lines, is 

 in the possession of Mr. Cuming, who obtained it with some shells 

 from the north-west coast of America, the measurement of which I 

 have adopted. 



Trichotropis inermis. Tri. testd ovatd, soUduld ; anfractibus 



quaternis rotvndatis, multicostatis, longitudinaliter Icevissime stri- 



atis; costulis subcBqualibus, planulatis, inermibus; aperturd oblongd, 



canali brevi desinente ; umbilico mediocri ; labia interno producto. 



Axis 1\ lin. 



Hab. Sitka, North-west America. In company with the preceding. 



In shape and outline this shell approaches T. borealis. It will be 



readily distinguished from any hitherto known species by the absence 



of armature on the epidermis, in which we lose sight in the instance 



before us of one of the characters of the genus. The whorls are 



rounded and separated, as in the other species, by a deep suture. 



The last whorl is remarkable for the strong ridges which it bears at 



rather distant intervals, marking the termination or commencement 



of the periodical stages of growth. 



In the method of formation of the canal there is a close affinity in 

 this shell to some Cancellarice, particularly in the angular- mouthed 

 species, and the affinity is extended to the character of the whorls and 

 their connexion by the suture. 



Trichotropis flavida. Tri. testd oblongd, tenui ; spird elatd; 

 anfractibus septenis tricostatis, ultimo inferne quadricostato ; epi- 

 dermide pallide corned indutd ; aperturd angulatd, ad basin obliquk 

 truncatd; canali brevissimo ; umbilico parvo, lineari. Axis 8 lin. 



Hab. ? 



Allied to T, cancellata, but is a more delicate and elongated shell ; 

 and the epidermis, though having some shreds attached to it, is 

 destitute of the bristled armature. A single specimen is in the col- 

 lection of Mr. Cuming, without any history. 



Typhis quadra tus. Typ. testd subquadratd, fused vet albidd, lineis 

 pallidis transversis ; quadrifariam varicosd; varicibus crassis, 

 acutis, ad spiram commixtis, superne nodulosis, in spinis appressis 

 desinentibus ; tubulis subrectis vel deorsiLm inclinatis ; canali me- 

 diocri later ali. Axis 11 lin. 



Hab. Gulf of Nicoya and the Bay of Guayaquil. Dredged from a 

 muddy bottom in from seven to eighteen fathoms. 



