. The illustrated natural history [microform]. Reptiles; Fishes; Mollusks; Natural history; Reptiles; Poissons; Mollusques; Sciences naturelles. CRUSTACEA. Having now completed our brief survey of the insects, we proceed to tl-e Crustacea class m which are the lobsters, crabs, shrinips, water-fLas^ul a l,o,st ol other lamihar beings. Even tlie Cirrhipeds, popularly knoin under the mim of Barnacles, are members of this large class, and i num'be'i. of c^irior LS, which We uut. uxtely been classed with the spiders, are now ascertained to belong to the Crus acea 1 hese beings c
. The illustrated natural history [microform]. Reptiles; Fishes; Mollusks; Natural history; Reptiles; Poissons; Mollusques; Sciences naturelles. CRUSTACEA. Having now completed our brief survey of the insects, we proceed to tl-e Crustacea class m which are the lobsters, crabs, shrinips, water-fLas^ul a l,o,st ol other lamihar beings. Even tlie Cirrhipeds, popularly knoin under the mim of Barnacles, are members of this large class, and i num'be'i. of c^irior LS, which We uut. uxtely been classed with the spiders, are now ascertained to belong to the Crus acea 1 hese beings can be easily sepamted from the insects on account of thd general struduiT, the head and throat being fused into one mass, called technicaHy t 'e eephalothorax; the number of limbs exceeding the six legs of the insects â and tliP mo p of âg, which is by gills and not by air-tubes. As°a neces aircot'ec i ne^^^^^^^ ast-nieutionedstructui^,,theCrustace.^^^^^ possess no spiracles, such as are foZun all thu .tages of insect lite from the larva to the imago. They under-o a wel - iwke metainorphosis, and m those creatures whose development is best known, the chancre of ,l,ape ,s so entire as to have led the earlier zoologists to consider the undeveloped Crus- tacea as separate species Tliey may be also distinguished from the spiders by 1 e prfseiice 0 a series of feet, or rather of locomotive organs arranged under the abdomen well a by the metamorphosis of their earlier stages, a phenomenon which is not known to take place among the spiders. "-uuwu Tlie name of Crustacea is sufficiently appropriate, and is given to these creatures on amnuit ot the hard shelly crus with which their bodies and limbs are covered, a coverin!! wliicli, m some cases is of such flinty hardness as to be used for the puii^ose of sharpen" n,g kmves, and in others, attains a glossy polish which reminds the observer of -iLed porcelain. oia^cu As our space is rapidly diminishing, we must
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Keywords: ., bookcentury1800, booksubj, booksubjectfishes, booksubjectmollusks
