132 UNIVALVES—— MUREX. 
The next division comprises those species which are 
commonly known by the name of Triplices, or more 
properly Purpure, as the animals inhabiting most of 
the shells of this class produce a liquid of a rich purple 
color, hence the whole genus has by some authors 
been called Purpura: the species are foliated, and 
have a much shorter beak than those of the preceding. 
The sutures are composed of crisped foliations, and 
acute angular ramifications, which are most striking- 
ly marked in the M. radix, and the pink and yellow 
mouthed varieties of the M. saxatilis. The number of 
rows in these sutures differs considerably, some, as 
the M. ramosus, &c. have but three, the M. scorpio 
has four, and the M. saxatilis five. 
The fourth division is composed of those species that 
have their sutures thick, protuberant, and rounded; such 
are the M. rana, M. femorale (or Gadroon-whelk) 
and M. lyratus. The fifth division consists of only two 
species, which are of irregular form. 
In the species of the sixth division, the form is more 
abbreviated and gibbous, they are also more or less 
spinous, and without a manifest beak: as the M. rici- 
nus, M. hippocastanum, M. neritoideus. 
The ninth division is composed of such shells as have 
a long, straight, subulate, closed beak, and unarmed 
with spines. The M. babylonius, and others of the first 
family, have a small fissure or incision on the extremity 
of the outer lip, close to the termination of the 
first whorl, a peculiarity solely confined to these 
species. 
