. Zoology for high schools and colleges. Zoology. PYONOOOmUA. 339 an.,; lt3l,-â-. The type of this class is the spider, which is character- ized by the pos- H Rii session of two or tliree pairs of spinnerets, which are jointed ap- pendages ho- mologous with the legs. Be- sides tracheae, ep st)Wf> spiders have a Fig. 366.âAnatomy of a spider, diagrammatic longitudinal SO-Called lung section tlirougli the body, aw, simple eyes and nerves leading CTfirr ^Ofi T^ to them from the brain (supra-CEsophageal ganglion, off); \ &⢠"""5 â '-';> ore,, mandibles ; ta^, palpus of ma
. Zoology for high schools and colleges. Zoology. PYONOOOmUA. 339 an.,; lt3l,-â-. The type of this class is the spider, which is character- ized by the pos- H Rii session of two or tliree pairs of spinnerets, which are jointed ap- pendages ho- mologous with the legs. Be- sides tracheae, ep st)Wf> spiders have a Fig. 366.âAnatomy of a spider, diagrammatic longitudinal SO-Called lung section tlirougli the body, aw, simple eyes and nerves leading CTfirr ^Ofi T^ to them from the brain (supra-CEsophageal ganglion, off); \ &⢠"""5 â '-';> ore,, mandibles ; ta^, palpus of maxilla ;,; U, first pair of legs, f>nTnnnsprl nf 6,-i,, succeeding pairs ; A" head ; Sr, thorax ; // hind-body >- " "^ F " » ^^ ^^ "'â or abdomen; Ha, heart or dorsal vessel; L, lung in front of several IcaveS the opening of the oviduct ff; the spinning-glands (»p) con- . , _ . _ , _ nect with the spinnerets. »p W'. The digestive tract is ^ haded, mto Whlch the and m the abdomen enveloped in the liver.âAfter Graber. , , -, n blood flows, and is thus aerated. In Lycosa the blood flows through the heart from the head backward. There is a great range of structure, from the lowest mites to the spiders, certain mites having no heart, no tracheae, very rudimentary mouth-parts, and no brain, there being but a single ganglion in the abdomen. Order 1.âThe Pycnogonida are marine forms, without air- tubes, with four pairs of long legs, into which co3cal prolonga- tions of the stomach pass, as seen in Pig. 307. Order 2. Tardigrada.â The bear animalcules (Fig. 308) are related to the mites. In these singular beings the ovary and testis exist in the same individual. Macrobiotus Americanus Pack, is common in sphagnum swamps. Like the Rotatoria, these low forms are capable of revivifying after being apparently dead and dried Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabi
Size: 2091px × 1195px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookpublishe, booksubjectzoology
