. The study of animal life [microform]. Zoology; Zoologie. CHAP. XV Backhoneless Animals 239 The members of the last four classes usually breathe by means of air-tubes or tracheae, which penetrate into every part of the body, or in the case of spiders and scorpions, by " lung-books," which seem like concentrated and plnited trachere. The King-crab (Limulus), which is very often ranked along witli Arachnids is aquatic, and breathes by peculiar "; ' (a) Omstacea.—Except the wood-lice, which live under bark .ind stones, the land-CMl)s which visit the sea only at the
. The study of animal life [microform]. Zoology; Zoologie. CHAP. XV Backhoneless Animals 239 The members of the last four classes usually breathe by means of air-tubes or tracheae, which penetrate into every part of the body, or in the case of spiders and scorpions, by " lung-books," which seem like concentrated and plnited trachere. The King-crab (Limulus), which is very often ranked along witli Arachnids is aquatic, and breathes by peculiar "; ' (a) Omstacea.—Except the wood-lice, which live under bark .ind stones, the land-CMl)s which visit the sea only at the breeding. Fig. 45.—Nauplius of Sacculina. (From Fritz Mailer.) time, and some shore-forms which live in great part above the tide- mark, the Crustaceans are aquatic animals, and usually breathe by gills. Each segment of the body usually bears a pair of append- ages and each is typically double. Among these ap- I'tndagcs much division of labour is often exhibited, some l)eing sensoiy, others masticatory, others locomotor. In the higher forms the hfe-hjstory is often long and circuitous, with a succession of larval stages. The lower Crustaceans arc grouped together as Enfnmostraca. riiey are often small and simple in structure; the number of ^y^^,'^. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Thomson, J. Arthur (John Arthur), 1861-1933; Knight, Professor. Toronto : Morang
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1902
