MALACOLOGY. 



gone, and furnishing evidence of facts which, without 

 A knowledge of them so conveyed, would have ren- 

 dered the geological phenomena of nature a far greater 

 mystery than they now are. In this great work, 

 Lamarck has very accurately described a vast collec- 

 tion of molluscs, and doubtless would have gone on 

 to a greater extent, had not the loss of sight obliged 

 him to depend more upon the descriptions of others 

 than his own. To a naturalist, the loss of that pre- 

 cious sense must be fatal ; but we can onlv say that 

 the errors it has occasioned in some parts of Lamarck's 

 work are less in consequence and fewer in number 

 than might be imagined under such a cruel affliction. 

 During the period occupied in completing this work, 

 malacology had everywhere received an impetus, 

 and many eminent men in various countries contri- 

 buted their researches on this interesting subject. 

 In Germany, the works of Schweiger and Goldfuss 

 on molluscs particularly merit notice. In America, 

 those of Say and Lesueur. In Italy, Rafinesque. 

 In England, Donovan, Leach, Sowerby, and many 

 others. But these for the most part applied their atten- 

 tion to the conchological arrangement of mollusca. 



Leach, about 1821, commenced a description of 

 English molluscs, based upon the anatomical structure 

 of their inhabitants, and would doubtless have per- 

 fected his labours, had not a cruel malady for a time 

 deprived science and his friends of that benefit. His 

 views in all he did were philosophically correct, and 

 we are happy to add, that his health being perfectly 

 restored, we may yet hope to derive instruction from 

 his writings, as a recent letter from him mentions that 

 he is busily occupied in collecting and describing the 

 ntomology of Italy ; he does not indeed say for pub- 

 lication, but we trust such is his intention. In 1822, 

 Gray published, in the London Medical Repository, 

 an article which, however, maybe considered little 

 more than a translation of Lamarck's classification, 

 changing their denominations ; his observations at 

 that time on the opercula of molluscs, which he has 

 more recently embodied, are extremely interesting 

 and highly important in the study of malacology. 

 De Ferussac the younger, who had occupied himself 

 principally with the terrestrial and rluviatile molluscs, 

 with a view to extend and complete the work his 

 father commenced, wished also to attach a general 

 system of malacology to these molluscs, but we cannot 

 Admire the scheme, and it abounds with discrepancies. 

 As a work of art it is a magnificent one, and equal 

 to anything yet published in graphic verisimilitude. 

 Having thus, with a rapid course, traced the outlines 

 of improvement effected in malacology by naturalists, 

 down to the period at which the system has taken a 

 pronounced shape, by De Blainville and other writers, 

 we will not stop to enumerate the subsequent valuable 

 information derived from the detached labours of a 

 number of eminent naturalists, too numerous to be 

 here mentioned, whether as anatomists or zoologists ; 

 but in thus acknowledging the obligations of science 

 to them generally, we trust we shall not be thought in- 

 vidious in mentioning particularly the name of Mr. 

 Richard Owen, Professor of Comparative Anatomy, 

 R.C.S.L., whose early career as a zoologist is 

 stamped with so much excellence, that well-founded 

 hopes may be entertained of his becoming our English 

 Cuvier, should health keep pace with his mental exer- 

 tions in the study of natural creatures. A want of space, 

 as we have constantly reason to regret, now fetters 

 our wish to have made a more minute chronological 



history of the writers on that part of malacology 

 which embraces descriptions of the animals only; and 

 we must, therefore, proceed to give an outline of the 

 system we have adopted as our guide, with some 

 general account of the structure of these extraordi- 

 nary animals comprised under the name of molluscs. 

 It is scarcely necessary to say that the mollusca are 

 found abundantly distributed over every part of the 

 globe's surface in the seas, rivers, sands, forests, and 

 plains. Their number is incalculable, and the 

 form of their bodies is beyond every thing extra- 

 ordinary, and would baffle any attempt at a de- 

 scription of most of them, with regard to a clear 

 definition of any shape approaching mathematical 

 symmetry ; thev, however, possess some general fea- 

 tures which are fixed and constant. They are never 

 articulated ; generally of an oval form, more or less 

 elongated ; sometimes convex above and plane be- 

 neath, sometimes convex above and below; the sides 

 often compressed, and others greatly attenuated. In 

 a great proportion of the cephalopoda, the upper part 

 of the body is spirally rolled in the form of their 

 covering, and some are so singularly constructed that 

 no intelligible account can be given of their figures 

 without seeing them before our eyes ; but we never 

 admit, the unphilosophical term of a shapeless mass 

 to any thing in nature, form resulting from purpose, 

 and that defined by matter. A great number of these 

 animals exhibit a distinct separation between the head 

 and the body, as in the Sepia ; it is less marked in the 

 Doris, a specimen of which is here figured; and in some 



Doris cornuta. 



the head, properly so called, does not exist in a distinct 

 form ; from which cause they are called AcephaUi, or 

 headless animals. The distinction of neck, chest, abdo- 

 men, and tail, is still less evident ; the body presenting 

 merely a mass united, or sometimes subdivided verti- 

 cally, but never as it were split in a direction from 

 the front part backwards. The bodies of these animals 

 are very rarely furnished with locomotive appendages, 

 properly so called in other animals ; but they some- 

 times possess cutaneous expansions, more or less 

 developed, which assist progressive motion, and it is 

 only in the articulated molluscs that these parts 

 assume a form more analogous to those of insects. 

 The skin which envelops their bodies is constantly 

 soft and spongy, so that it is Contractile in every 

 direction, in this is situated the colouring pigment, 

 which is often of a vivid colour. It may be sup- 

 posed that the mucous cysts, or concealed cells on 

 the superfice of the skin are extremely numerous, 

 judging from the large quantity of matter distributed 

 generally over its surface ; but it is frequently very 

 difficult todiscover them. In some species the mucous 

 pores are more evident. No true hairs are found on 

 these animals ; sometimes, however, the epidermis of 

 the shell is prolonged externally as it were, and pre- 

 sents a fringed or hair-like appearance, observable in 

 some of the helices and bivalves. In some species 

 of the Chitons this is very remarkable, for these cal- 

 careous horny points are frequently placed in small 

 tufts on both sioVs. of the body. As it frequently 



