Historical Account of Tcstaceological Writers. 193 



cepting Lister, and his information is (on this subject at least) in 

 no respect ample. 



In the Fundamenta Zoologica of 



BRUNNICH 



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 Bucciuum into the same number. These alterations are 

 strictly reconcilable Avith Linnean principles, yet it may be rea- 

 sonably doubted how far they are necessary. 



At the head of those writers Avho 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 etjluviat ilium Historia" Ave have a sketch 

 of his proposed aiTangement of the land and river Testacea, Avhich, 

 according to this author, form two very distinct orders, though 

 not differing from each other so Avidely as the fresh-Avater 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 Avhich they protrude. Hence the Linnean genus 

 Limax is included in the testaceous instead of the molluscous 

 order. The Avork in Avhich these outlines are given is published 

 in tAvo volumes, the first begun in 1773, and the second in 1774: 

 the latter relates solely to the subject of Avhich Ave are treating ; 

 and its preliminary matter, in a physiological and anatomical 

 point of vicAv, is of a very curious and instructive nature. 



]n 1776 our author printed a Prodromus of the Zoology of Den- 

 mark, containing concise descriptions of every known species in- 



voL. viT. 2 c habiting 



