1s 
keeled, and furnished on the lines of the striz 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, soliduld; anfractibus 
quaternis rotundatis, multicostatis, longitudinaliter levissim?_stri- 
atis; costulis subequalibus, planulatis, inermibus ; aperturd oblongd, 
canali brevi desinente ; umbilico mediocri ; labio interno producto. 
Axis 7} lin. 
Hab. Sitka, North-west America. Obtained 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 Cancellaria, particularly in the angular-mouthed 
species, and the affinity is extended to the character of the whorls and 
their connexion by the suture. 
TricuoTropPis FLAvIDA. Tri. testd oblongd, tenui; spird elatd ; 
anfractibus septenis tricostatis, ultimo inferné quadricostato ; epi- 
dermide pallid corned indutd ; aperturd angulatd, ad basin oblique 
truncata; canalt 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. 
Typruis, Montfort. 
Typuis quapratus. Typ. testa subquadratd, fuscd vel albidd, lineis 
pallidis transversis ; quadrifariam varicosd; varicibus crassis, 
acutis, ad spiram commiztis, superné nodulosis, in spinis appressis 
desinentibus ; tubulis subrectis vel deorsim inclinatis ; canali me- 
diocri laterali. Axis 11 lin. 
Hab. Gulf of Nicoya and the Bay of Guayaquil. Dredged from a 
muddy bottom in from seven to eighteen fathoms. 
Allied to Typhis Sowerbii, but distinguished from it by its squarish 
