A MONOGRAPH OF THE GENUS 

 TRICHOTROPIS, Brod. and Sowb. 



Char. Gen. Testa spiralis, earinata ; apertura magna, angulata, 

 infra subacuminata, Integra; columella oblique truncata, anfrac- 

 tibus paucis, ultimo magno ; epidermide cornea, super carinas 

 frequenter ciliata; operculo corneo, non spirali, nucleo terminali. 



A genus of carinated spiral shells, belonging to the Buccinum 

 family, but differing from Buccinum in the want of a distinct 

 canal. The thin epidermis with which the shell is covered is in 

 many species ciliated at the keels. 'Operculum non-spiral, with a 

 terminal nucleus. 



Species. 



1. borealis, Brod. et Sowb., (f. 1, 2, 3). — Subfusiformis, 

 umbilicatus, anfractibus angulatis, carinis tribus crassis superiori- 

 bus, et duabus tenuioribus inferioribus cinctis, apertura ple- 

 rumque pallide rosea, subtrigona, ad terminum inferiorem acumi- 

 nata, labro ad costarum terminos angulato ; epidermide super 

 costas duplicatim ciliata. — Specimens from different localities 

 differ much in relative proportions, some being much more acu- 

 minate than others. Eig. 1 may be taken to represent the typical 

 British form ; fig. 3 is drawn from a specimen hi the British 

 Museum, from Behring's Straits, and fig. 2 is the acuminate form 

 which has been named T. Atlantica. 



2. costellata, Couth., (f. 6). — Quam T. borealis tenuior, 

 costis tenuioribus, inferioribus magis numerosis. — Thinner than 

 T. borealis, with thinner ribs ; instead of two rather stout ones 

 beneath the three upper ones, there are four or five very small. 



3. iNERJiis, Hinds, (f. 14). — Quam T. borealis crassior, carinis 



crassioribns rotundis, umbilico lato, apertura subpyriformi, labro 

 integro, epidermide inermi. — A thicker shell than T. borealis, 

 with thicker and closer ribs, which do not modify the form of the 

 outer lip. 



