. An introduction to zoology [microform] : for the use of high schools. Zoology; Zoologie. HIGH SCHOOL ZOOLOGY. 203 are the most imi^ortaut. Both havo the two |mir3 of mouth- appendages and the four pairs of walking legs, but the form of the body is very different in the two groups, on account of the separation of the abdomen in the spidera proper, by a slender stalk, and the presence at its extremity of •ihe spin- nerets (Fig. 137). Some of the chief structural peculiarities of the spiders may be gathered from Fig. 138. The two-jointed chelicera? terminate in a powerful claw, perforated by th
. An introduction to zoology [microform] : for the use of high schools. Zoology; Zoologie. HIGH SCHOOL ZOOLOGY. 203 are the most imi^ortaut. Both havo the two |mir3 of mouth- appendages and the four pairs of walking legs, but the form of the body is very different in the two groups, on account of the separation of the abdomen in the spidera proper, by a slender stalk, and the presence at its extremity of •ihe spin- nerets (Fig. 137). Some of the chief structural peculiarities of the spiders may be gathered from Fig. 138. The two-jointed chelicera? terminate in a powerful claw, perforated by the duct of a. Fig. 138.—Diagraniinatic section of a'spidur—£>;*/•«. (After Euierton). o, b, upper and lower lips; c, xsophagus: , upjier and lower muscles of the euck- iiig stomach; e, stomach ; ff, ligaments attached to diaphragm under the stomach ; k, jpiier, j, lower, nerve-ganglion ; /, ner\o to legs and palpi; m, in, branches of stom- ach ; n, poison-gland; o, intestine; j>, licurt; r, lung; s, ovary; t, trachea; u, spinning glands. jK)ison-gland. Between the bases of the pedipalpi is the mouth, which leads by an cesophagus into a sucking stomach, dilatable by muscles, and provided with lateral cceca. The abdominal part of the intestine is provided with a liverj and with Malphigian tubes (slender coeca arising from the hinder end of the intestine in air-breathing Arthropods, and discharging the function of kidneys). The heart is elongated like that of the scorpion and of the lower Crustacea, but the nervous cord is concentrated into the thorax. Above the ceso[)hagu8 is the brain, which sends nerves to the simple (not facetted) eyes, the arrangement of which on the head is of great use to systematists. The numerous lungs of the scorjiion are only reprasented here by two air-sacs (four in the trap-door spiders), while, in addition^ a f>.-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for reada
Size: 2668px × 936px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookpublishe, booksubjectzoology
