Historical Account of Testaceological J Writers, 193 
cepting Lister, and his information is (on this subject at least) in 
no respect ample. 
In the Fundamenta Zoolomca of 
BRUNNICII 
we find a few genera added to those of Linnaeus, but only among 
the univalves; the genus Nautilus being divided into three, and 
that of Buccinum into the same number. These alterations arc 
strictly reconcilable with Linncan principles, yet it may be rea- 
sonably doubted how far they are necessary. 
At the head of those writers who have contended for what may 
be called the natural system of Testaceology, or a system founded 
on the stucture and habits of the inhabitants of shells, may be 
placed 
OTHO FREDERIC MULLER, 
one of the most laborious and sagacious zoologists of his age. In 
his " Vermium terrestrium et fluviat ilium Historia " we have a sketch 
of his proposed arrangement of the land and river Testacea y which, 
according to this author, form two very distinct orders, though 
not differing from each other so widely as the fresh-water and 
the maritime. The characters of his genera are taken chiefly 
from the shape of the tentacula of the animals; in the bivalves, 
from the siphon which they protrude. Hence the Linnean genus 
Limax is included in the testaceous instead of the molluscous 
order. The work in which these outlines are given is published 
in two volumes, the first begun in 1773, and the second in 1774: 
the latter relates solely to the subject of which we are treating ; 
and its preliminary matter, in a physiological and anatomical 
point of view, is of a very curious and instructive nature. 
In 1776* our author printed a Prorfromus of the Zoology of Den- 
mark, containing concise descriptions of every known species in- 
vol. vii. 2 c habiting 
