ON MOLLUSCS IN GENERAL 
Iy what precedes we have treated of the greater part of those 
animals that have no internal skeleton or no vertebrae. There still 
remain however for our consideration many that, in the system of 
Linneus, were referred to the class of worms, but which by Cuvimr 
were, first as a class, afterwards as a larger group constituting a 
primary form (¢ypus), collected together and separated from the rest 
of the worms”. Since they do in reality form such a group, which 
' Compare on this division of the Animal Kingdom, amongst others : 
M. Lister Exercitatio anatomica de Cochleis maaime terrestribus et Limacibus. 
Londini, 1694, 8vo. 
Ejusd. Hist. sive Synopsis method. Conchyliorum et Tabularum anatomicarum editio 
altera. Recensuit et indicibus auwit G. HuDESFORD, Oxonii, 1770, folio. 
M. Avanson Hist. natur. du Sénégal. Coquillages. Avec 19 pl. Paris, 1757, 4to. * 
J. X. Port Testacea utriusque Sicilie eorwmque historia et anatome, Tabulis cn. 
ilustrata, Parme, fol. Tom. 1. 1791, Tom. 11. 1795, Tom. m1. Pars prima posthuma ; 
edid. 8. DELLE Cutasn, Parme, 1826, Pars altera, auctore S. DELLE CHIAJE, Parme, 
1827 (this part remains unfinished), 
Cuvier Mémoires pour servir & U Histoire et & UVAnatomie des Mollusques, avec 
35 Pl. Paris, 1817, 4to. 
EK. Forses and 8. Hanuny Nat. Hist. of British Mollusca and their Shells. 
London, 1848—s0, 8vo. 
G. Jounston An Introd. to Conchology; or Elements of the natural Hist. of 
Molluscous Animals. London, 1850, 8vo. 
As manuals the following especially may be consulted : 
Lamarck Hist. nat. des Animaux sans Vertéebres, 2e édit. par DESHAYES et 
Mitne Epwarps, Tom. vi. 1835 ; H. Ducroray DE BLaInvitLE Manuel de Malaco- 
logie et de Conchologie, 1 Vol. 8vo, Paris et Strasbourg, 1825—1827, avec 107 Planches, 
and G. P. DesHayeEs Traité elémentaire de Conchologie, Paris, 1838 and foll. 8vo. 
(hitherto only g numbers have appeared). We shall principally refer to these two 
last works, besides Gu&RIN’s Iconographie, for the figures, and only occasionally quote 
more extensive works of plates, as those of Martini and CHEMNITZ, KinnmER, &c. 
2 See p. 33 and 208. To the works of Cuvier referred to in the last of these 
pages, there ought to have been added one that was printed separately from the 
Decade philosophique, a journal with which I am not further acquainted, and which 
now lies before me: it is entitled, Mémoire sur la structure interne et externe et sur les 
