686 



CANCRIDA CANCROMA. 



of the Linnaean genus, and thus by the assistance of 

 three or four other still more interior sections, to 

 bring his inquiry into the lowest possible compass. 

 In doing this, however, a sufficient regard has been 

 paid to the authority of Linnaeus, by converting his 

 genera into families, terminating uniformly, according 

 to the admirable plan of Mr. Kirby, in idee. Sub- 

 families have been introduced, as we have shown in 

 the article BKACHELYTRA, which are again subdivided 

 into genera and sub-genera, which present varieties 

 in structure of their different organs, while they agree 

 in possessing the characters of the great family to 

 which they belong. Now the advantages of this 

 plan of names are evidently these: 1st, The pecu- 

 liar construction of an animal is instantly called to 

 mind by the naming of its modern generic or sub- 

 generic names, whereas if the old Linnaean (but now 

 family) title were employed, a very indefinite idea 

 would alone be obtained : for instance, if we were 

 merely told that a friend had observed the habits of 

 one of the two thousand five hundred Carabidce, we 

 should be almost as completely in the dark as to its 

 precise structure, as though we had been told that it 

 was a beetle. 2nd, The beautiful perplexity arising 

 from the employment of stars, and daggers, and 

 asterisks, for sections of the Linnaean genera, is en- 

 tirely removed. Those who, for instance, have 

 studied as we have done, the invaluable Monographia 

 Apum Anglia of Mr. Kirby, will readily agree with 

 us, that the benefit arising from the use of names, 

 which in general carry some structural idea with 

 them, is alone sufficient to overbalance the difficulty 

 of bearing in mind either the sectional marks of dis- 

 tinction noticed above, or the names employed iii 

 their stead : and 3rdly, The immense saving of time 

 gained by the student in investigating the species of 

 his collection ; since, if two thousand five hundred 

 species of Carabi composed but one genus, as they 

 do according to Linnaeus, what person can be found 

 with either time or inclination to identify the species 

 of even a local collection. For general purposes, 

 indeed, the employment of the old Linnaean names 

 would, in many cases, be sufficient but for the ends of 

 science, not only the modern generic but also sub- 

 generic names must be employed ; and a plan has 

 been suggested by Mr. Robert Brown, which has the 

 advantage not only of not materially disturbing the 

 names already existing, but also of insuring the co- 

 operation of two classes of naturalists at present 

 opposed to each other, namely, by introducing the 

 modern sub-generic name in brackets between the 

 old generic and specific name, thus we should call 

 the devil's coach horse % fi<zure<\aisStaphylinus(Goeritis) 

 vlens. " This," as Mr. Brown observes, in the ap- 

 pendix to the narrative of travels and discoveries 

 in northern and central Africa, " is analogous to the 

 method followed by the Romans in the construction 

 of the names of persons, by which not only the original 

 family, but the particular branch of that family to 

 which the individual belonged, was expressed. Thus 

 the generic name corresponds with the nomen (Cor- 

 nelius), the name of the section with the cognomen 

 (Scipio), and that of the species with the prcenomen 

 (Publius)." 



Naturalists have agreed in retaining for (he old 

 generic name those species which were more striking 

 instances of the Linnaean groups. Thus, returning 

 to the animals which have led us into this long, but 

 we trust not useless digression, we find the large 

 edible crab of the European coasts (Cancer pagvrus, 



LinnJ, regarded as entitled to retain the old generic 

 name of Cancer by most authors, although M. Milne 

 Edwards has very injudiciously formed it into a dis- 

 tinct genus, named Platycarcinus. The other genera 

 in this family are Carpilius, Zozymus, Lagostomu, 

 Xantho, Chlorodius, Panopeus, Zius, Pseudoear- 

 cinus, Etisus, Pilumnus, Ruppellia, and Perlmcla. 

 These genera are for the most part established by 

 Leach and Edwards upon structural differences alone, 

 scarcely any thing being known of their habit*. 

 Those printed in italics are natives of our coasts. 



C AN C RID A (De Montfort). A genus of mol- 

 luscs, united by other authors to the genus Crcpidu- 

 lina, of which it is manifestly a species. 



CANCROMA (Boatbill). A genus of birds 

 belonging to Cuvier's Prcssirostral, or compressed- 

 billed family of Echasxiers, long-legged or stilt birds. 

 There is only one known species, a native of the 

 tropical parts of South America ; but the manners, 

 and especially the appearance of this species, are 

 very peculiar. It does not appear that the name 

 Cancroma, or " crab-eater," is very accurately applied 

 to this bird, though it does live near the waters, and 

 it is in all probability a feeder upon the Crustacea 

 which these afford, but it is an inland bird ; and as 

 we more exclusively apply the word crab to marine 

 Crustacea, it were desirable that another epithet 

 should be given to this bird. 



The boatbill bears a considerable resemblance to 

 the heron family, more especially to the night heron. 

 As is the case in those birds, its bill is of great 

 power, and its neck capable of much and rapid 

 motion, so that it can strike and seize with great 

 force and much celerity. Its bill is, however, very 

 different in shape from those of the heron, and the 

 epithet pressirostral does not apply to it, as its bill is 

 the very reverse of being compressed. This, by the 

 way, shows how injudicious it is to name a family of 

 birds from the form of any particular organ, and, 

 indeed, the general incorrectness of a system which 

 classes birds by the bills at all. The food of birds is 

 so miscellaneous, and the parts of their feeding 

 apparatus so few as compared with those of mam- 

 malia, that they do not form a sufficient number of 

 distinctive characters. In the mammalia themselves 

 it is not the form of the jaws from which we infer 

 the feeding, and, consequently, the general characters 

 of the animals ; it is from the teeth. Birds have no 

 teeth ; and before we can come at any thing like a 

 satisfactory conclusion as to that food on which they 

 feed, we must take an average of three qualities the 

 form of the bill, the texture and substance of it, and 

 the character of the tomia, or cutting edges of the 

 mandibles. 



Viewing the boatbill in this, the only rational way 

 in which we can view it, it is more nearly allied to 

 the herons than with any other birds ; and, notwith- 

 standing the dissimilarity in the shape of its bill, it 

 might, without much impropriety, be included in the 

 same family, if not in the same genus. 



The bill of this bird has certainly a very singular 

 appearance. It is very much extended laterally, and 

 seems like two small boats, or rather perhaps two 

 spoons applied with their concavities towards each 

 other. These lurge mandibles are very strong, their 

 cutting edges are exceedingly sharp ; and though 

 they are not serrated throughout the whole length, 

 as is the case of those of the herons, yet there is a 

 strong and sharp tooth on each side of the upper 

 one, near the point. From this structure of the 



