TESTACEOUS FISH. 



351 



or turbinated, which consists of one piece, like 

 the box of a snail ; secondly, the bivalve, con- 

 sisting of two pieces, united by a hinge, like 

 an oyster; and, thirdly, the multivalve, con- 



dination of all its parts; in the admirable sagacity with 

 which the families or genera are limited ; in the assump- 

 tion of more stable characters for these, and for the clear 

 distinct manner in which they are applied ; in the 

 suitableness of its nomenclature; in the invention of 

 trivial names which give a facility in writing hitherto 

 unknown, and was a welcome relief to the memoiy ; in the 

 conciseness of the specific characters and the skill with 

 which those characters were chosen ; in the regular in- 

 dication of the stations which the species occupy on the 

 globe ; and in the beauty of the more extended descrip- 

 tions, and the peculiar felicity of language in which the 

 thoughts suggested by any remarkable structure in the 

 species under review are conveyed to us. That merits 

 of this kind should secure him something more than ap- 

 probation was natural: there was much excellence in it 

 which prejudice or jealousy only could not see, and 

 which folly alone would have rejected ; and while every 

 collector and amateur found it easy to be understood, 

 ready in practice, and neat in nomenclaturing their 

 cabinets, their pursuit assumed the garb of science when 

 they could tell the scorner that they were following the 

 steps, and had the sanction, of a man whose genius has 

 justly won him a place in the first rank of those whom 

 succeeding ages continue to venerate for the good they 

 have done in the promotion of useful knowledge. 



While the eyes of almost all were turned to this 

 northern luminary for light to guide them in their pur- 

 suit, or as an object by barking at which a few drew 

 notice on their littleness, Jussieu of Paris, the admirer 

 of Linnaeus' genius and industry, and his correspondent, 

 was explaining to his select but few disciples the prin- 

 ciples of what has been commonly called the " Natural 

 System." Jussieu's profound studies were confined to 

 botany, but he had colleagues and contemporaries who 

 attempted their application to conchology, and whose 

 want of success is to be ascribed mainly to the meagre- 

 ness of the anatomy of the mollusca then attained, to the 

 fewness of the observations made on the living species, 

 and in part also to the imperfection of the views of the 

 authors. Daubenton, the colleague of Bufibn, so early 

 as 1743, insisted on a knowledge of the animal as 

 necessary to form a natural classification of shells ; and 

 in 1756, Guttard, who was the personal friend of Jussieu, 

 not only gave his sanction to this opinion, but showed 

 its practicability and excellence by defining, from the 

 peculiarities of the animal and shell combined, a con- 

 siderable number of the univalves, comprehending among 

 these, in evident agreement with their relations, though 

 contrary to general use, the slugs, the Aplysia, and the 

 Bulloea. But the fullest attempt of this kind was made 

 byAdanson, whose work on Senegal was published some 

 years before Linnseus had given the last revision to his 

 system. Impelled by an indomitable enthusiasm, Adan- 

 son visited Senegal, under many disadvantages, to ex- 

 amine and describe the natural productions of a tropical 

 climate ; and for this purpose he made very extensive 

 collections in every department of nature, but of his 

 great work the first volume only, containing the outline 

 of his travels and his account of the shells, was ever given 

 to the people. The character of this volume has risen 

 with the progress of the science, and it is more valued 

 by the conchologists of the present day than it was by 

 the contemporaries of its author. He had some personal 

 peculiarities too visible in his writings which could 

 not fail to hurt his popularity : an austere temperament, 

 which caused him to treat his fellow-labourers with con- 

 temptuous acerbity, a -mind that would neither bend to 

 nor treat with respect the prejudices, as he deemed them, 



sisting of more than two pieces, as the Acorn- 

 shell, which has not less than twelve pieces 

 that go to its composition. All these kinds 

 are found in the sea at different depths, and 



of his age, an unflinching severity in criticising the 

 writings of others, and a pertinacious tenacity of his own 

 views, while some barbarisms he attempted to intro- 

 duce into the nomenclature of conchology repelled the 

 naturalists of a too nice taste, and the very extent of his 

 requirements from those who claimed to be naturalists 

 operated against him, for it was not to be supposed that 

 mere collectors or virtuosos were to enter on so difficult 

 a path, or would be willing to allow themselves to be 

 pushed aside as idlers, and put without the pale of the 

 scientific circle. Shell-fish were, according to him, dis- 

 tinguishable, in the first place, into " Limagons" and 

 "Conques;" the former were subdivided into univalves 

 and operculated univalves, and the conques into bivalves 

 and multivalves ; these primary families were still 

 further divided into smaller groups from the position of 

 the eyes in the Limagons, and from the figure of the 

 respiratory tubes in the Conques. Now it was a pure 

 arbitrariness in him to fix upon the opercnlum as a part or 

 organ of primary value, for there is nothing in its use or 

 position to justify the choice, nor did he attempt, by any 

 analysis, to show that it was a regxilator of structure and 

 habits; and it was equally arbitrary to divide the bivalves 

 into two sections on the mere existence of a few 

 additional pieces over the hinge, for these pieces were 

 not proved to be an index to the animal's economy. 

 But Adanson's services to conchology are very great, 

 of those of its labourers who have passed in review we 

 place him next to Lister. He has the merit of having 

 altogether removed from the Testacea the Lepas and 

 Balani, whose structure he saw was modelled after tho 

 type of another category ; his interesting discovery of 

 the Vermetus was a fine illustration of the shell being of 

 itself useless as a character in natural history j and his 

 knowledge of affinities was made evident by the acute 

 ness which led him to approximate the Teredo to the 

 Pholas. If not the first to point out the importance of 

 the operculum, he was undoubtedly the first who knew 

 its value as an index to natural relationship between 

 genera ; perhaps the first who was fully aware that the 

 entireness or canaliculate formation of the aperture of 

 the shell gave an insight into the habits of the snail in 

 regard to food ; the first too to point out fully the in- 

 fluence of age and sex in altering the shape of the shell, 

 and more especially of its aperture ; the first to describe 

 and delineate the animal tenant of many genera ; and 

 although his attention was exclusively directed to ex. 

 ternal characters, yet we are above all indebted to him 

 for his strong advocacy of the maxim that the anatomy 

 of the animal was the sole sure foundation of a rational 

 arrangement which had in view the mutual affinities of 

 the objects it attempted to classify, and present them not 

 fancifully commixed as they might be placed in a 

 museum, but according to those characters which nature 

 itself had given them of affinity or dissemblance. 



The example of Adanson was followed by Geoffrey 

 who, in a history of the shells found in the vicinity 

 of Paris, attempted to arrange them on the external 

 anatomy of their animals ; and by Muller, who described 

 in the same manner the mollusca of the north of Europe. 

 The writings of Muller are still deservedly held in high 

 estimation. They contain the descriptions of many 

 novelties, and his descriptions of them, as well as of 

 species previously known, are remarkable for their 

 accuracy ; they are thickly strewed with notices of the 

 external anatomy and habits of those he had examined 

 alive ; and his style of writing is interesting, rising 

 occasionally to eloquence. As an observer and teller of 

 what he had observed, he claims a place among the first. 



