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Do Bluinville does not altogether agree with 

 Lamarck's arrangement of the species, and has 

 separated from them ull such as have the aperture 

 evidently canaliculated, as in the C. lima, which lie 

 considers to helium' properly to the Mnrices and 

 turriciilated TurhincUas. Of twelve recent species, 

 he says the habitat of such as are known is in the 

 Indian Feus and Senegal. De France enumerates 

 twelve fossil species, hut more have since been 

 described. In De Blainville's system this genus is 

 arranged with the family Entomostomata ; first order, 

 SephonobrancMata; second class, Paracephalophora. 



"CANCER1DJ3 (Leach). A family of crustaceous 

 animals belonging to the order Bracht/urrt, and cor- 

 responding with the genus Cancer of Fabricius, or 

 the Crabcs arques of Latreille (see BRACHYURA). 

 In this family, of which the common edible crab is 

 the type, the four posterior logs are terminated by a 

 narrow pointed and simple claw or hook, which is 

 not dilated into a plate for swimming, as in the 

 Portunida:, of which the small edible crab, sold in 

 the streets of London, is an example. The shell or 

 carapace is curved in front into an arc of a circle, 

 and gradually narrowed behind, being squared off 

 between the two hind legs. The claws of the fore 

 legs do not differ in size in the different sexes. The 

 ubdomen in the males is five-jointed, the central one 

 being the largest, and in fact composed of three 

 ioints soldered into one, that of the female being 

 formed of seven distinct joints. 



Mr. Milue Edwards unites this family and the 

 Porliniidcc, mentioned above, and which are certainly 

 very nearly related (their chief difference consisting 

 in the dilated claws at the extremity of the four 

 pairs of hind legs in the latter, whence they are 

 termed shuttle crabs) into one family, Cyclometopcs. 

 (See the article BKACHYURA.) 



It. is to be understood therefore, that the modern 

 family Ctinccridac does not, like the majority of the 

 families of insects, correspond in its limits with the 

 great Linmjean genus from which it takes its name, 

 but comprises only a small portion of the genus 

 Cancer of Linnaeus, which has been raised to the 

 rank of the order containing numerous families, sub- 

 families, genera, sub-genera, and species. 



This group of animals therefore, affords an oppor- 

 tunity of entering into a few observations upon the 

 modern nomenclature of natural history, a subject 

 respecting which we constantly hear great objections 

 raised. Let us not be understood, however, to wish 

 to give to the study of names more than its due 

 weight. Natural history is not a science of names 

 alone, we have living objects for the subjects of our 

 contemplation ; and blind indeed must he be to the 

 beauties of the visible world, who could look at a 

 plant or an insect with no other interest than that of 

 ascertaining its scientific name. The astronomer 

 would be worse than mad who would regard the 

 great luminaries of the universe with no other 

 feelings for the benefits which they bestow, than that 

 of a desire to prove their place in the " heavens 

 above." But whilst we thus uphold the superiority 

 of the observations of the economy, and natural his- 

 tory in its legitimate sense, of the animated world ; 

 let us not disregard one of its important, although 

 subservient adjuncts that of names. We apprehend, 

 indeed, that no one will deny their utility, the sup- 

 posed abuse, not the use of the system being objected 

 to. Should, however, any one object to the latter, 

 and amnn that nature may be studied in idl its 



details without the technical machinery of names, we 

 shall fee! no disinclination even to agree with him in 

 this latter observation, so far as his own experience 

 is concerned, but how greatly is the case altered 

 should he wish to impart, his knowledge. We have, 

 indeed, only to refer to the highly valued memoirs of 

 Reaumur, for a confirmation of our observations upon 

 the utility of names ; since it has unfortunately hap- 

 pened that many of his most interesting histories, for 

 want of a precise determination of the animals whose 

 habits are thus recorded, have been lost to science. 



Admitting then the necessity of names, we are 

 now to show the necessity of that extended system 

 of nomenclature which, from having been so much 

 paraded, to the exclusion of natural history, has 

 caused great clamour to be raised by those who were 

 led to believe, first, that our science was but a science 

 of names, and secondly, that the system of Linnoean 

 nomenclature was amply sufficient for every purpose, 

 hence that the great multiplication of the minor divi- 

 sions of the Linnacan genera was but an unnecessary 

 frittering of science, having not the least utility, and 

 tending only to disgust the student. Let us, however, 

 look more narrowly at the subject, and endeavour to 

 ascertain what are the grounds for these opinions. 

 It cannot be denied that the machinery of nomencla- 

 ture, like that of every other apparatus, must have 

 had both a commencement and a founder. Take, 

 for instance, the machinery of a time- piece, which in 

 the early stages of clock-making was most cumbrous, 

 notwithstanding its simplicity. Still, to a certain 

 extent, it fully answered the purposes of its construc- 

 tion, that of dividing the day into a certain number 

 of portions. By degrees, as the additions of the 

 minute hand, the striking apparatus, and that of the 

 divisions of a minute, of the repeater and that of the. 

 chimes were made, the machinery became more com- 

 plex ; and instead of simply turning round once in a 

 certain period, we find wheel revolving within wheel, 

 to an extent which to a savage has the appearance 

 even of life itself. 



Sucli is precisely the case with the nomenclature 

 of natural history. Linnams, the great inventor of 

 the system, was indeed so well acquainted with the 

 general relations of the great divisions of nature, that, 

 although it is certain that his botanical far surpassed 

 his zoological knowledge, it is a tribute which is 

 willingly bestowed upon him by all, that in the con- 

 struction of his general groups the modern naturalist 

 must be compelled to tread, for a great extent, in his 

 steps. Look, however, at the progress of zoology 

 since the days of this great master. Take a single 

 genus of insects for instance Carabus, of which he 

 described fifty-three species, and we find not fewer 

 than two thousand five hundred contained in the sin- 

 gle collection of the Baron Dejean, whilst the more 

 minute peculiarities of organisation, both internal and 

 external, have been studied with the greatest zeal by 

 numerous authors. The discoveries of later days 

 have likewise presented numerous groups, equal with 

 those of the genera of which he was ignorant. Now 

 this torrent both of novelties and of science has rendered 

 the old Linnaean genera of such amazing extent, and 

 so unwieldy, that entomologists, in their own defence, 

 have been compelled to institute subdivisions of va- 

 rious ranks; for instance, if a person wish to record 

 some fact concerning one of the Linntean Carabi, he 

 is enabled, instead of wading through the descriptions 

 of two thousand five hundred species, to reduce the 

 objects of his inquiry to one of the great sub-families 



