LITTORINIDZ. 337 
others so nearly resembling his, that he becomes bewildered in 
the mazes of distinctions, often without differences, despairs of 
identifying his object, and perhaps retires altogether from a 
rational and highly important pursuit, under the idea that the 
science is full of perplexities, which he, as a tyro, has neither 
time nor inclination to unravel. 
The unsatisfactory state of this branch of natural history 
originates in the practice of drawing up specific distinctions 
from the shell or a half of the animal; these are consequently 
arbitrary and artificial ; and though, in decided forms, this plan 
may produce correct results, it signally fails when structures 
begin to shade into each other; then the sheet-anchor, the 
animal, can alone solve doubts, and often shows that shells, 
apparently well marked by specific distinction, are not in 
reality distinct, and vice versd. 
This neglect to consult the most important, the soft parts 
of the animal, has in some measure been occasioned by the 
supposed difficulties of procurmg living objects for examina- 
tion, and a disinclination to enter into the imaginary repulsive 
details of dissection and anatomical inductions; every day’s 
experience diminishes these obstacles. Naturalists may be 
assured that every attempt to establish specific identity, with- 
out taking into account both the hard and soft parts of the 
animal, will be unsatisfactory and deceptive. The unpleasant 
operations of anatomy to persons of great sensibility may often 
be dispensed with, and, in the majority of cases of specific 
discrimination, are unnecessary. 
Every person can deposit animals in sea-water and describe 
their habitudes and external organs, as the head, tentacula, 
eyes, and how they are placed, whether at the external or 
internal bases of the tentacula; and if on pedicles, what is 
their proportion to the length of the tentacula; the shape 
of the foot, operculum, the mouth, and coloration of the 
animal, &c.; these points, with the sculpture of the shell, will 
in almost all cases ensure specific distinctions, and conse- 
quently remove the inconveniences of the arbitrary creation of 
species on conchological bases. 
I see with pleasure that the system I advocate has received 
Z 
