500 ON A REVERSED* SPECIES OF f'USUS^. 
is known to include the Murex despectus and corneus of 
British writets, as examples. 
In this section, it will form a group along with the Mu- 
rex contrarius of Sowerby"*s Mineral Conchology, vol. i. 
p. 63. tab. xxiii., distinguished by the whorls being re- 
versed. Perhaps they might constitute a new genus, to be 
denominated Heterqfusus. The Murex contrarius (now 
before me), which is found in gravel-pits in Essex and Suf- 
folk, and which is considered as extinct, differs from the 
recent one, which we have described, in size, and in the 
shape of the whorls, the mouth, and the pillar. Our species, 
indeed, acquires considerable interest from this circum- 
stance, that it is the only known representative of a tribe, 
inhabiting our seas at present, the Murex contrarius hav- 
ing probably flourished when the seas of Europe were 
peopled with a different series of molluscous animals. 
Manse of Flisk, ) 
February 21. 1823. j 
