. An introduction to zoology [microform] : for the use of high schools. Zoology; Zoologie. 198 IIIUII SCHOOL ZOOLOGY. i. tliat the four hiudmoHt abdoiuinal ftcgnientR arc coaleHced above into a sliiekl, from beneath which the last pair of logs pi*oject. The three pairH of legs in front of those servo for respira- tion, and the eggs are carried in the female on the under surface of the tiioracic segments. Terrestrial lHO])ods, like the common Woo<Mou8e (O^iiscus) and its allies, exhibit an interesting adaptation for breathing air; one of the pairs of abdominal legs being traversed by tubes w
. An introduction to zoology [microform] : for the use of high schools. Zoology; Zoologie. 198 IIIUII SCHOOL ZOOLOGY. i. tliat the four hiudmoHt abdoiuinal ftcgnientR arc coaleHced above into a sliiekl, from beneath which the last pair of logs pi*oject. The three pairH of legs in front of those servo for respira- tion, and the eggs are carried in the female on the under surface of the tiioracic segments. Terrestrial lHO])ods, like the common Woo<Mou8e (O^iiscus) and its allies, exhibit an interesting adaptation for breathing air; one of the pairs of abdominal legs being traversed by tubes which have the same function as the tracheu3 of insects. Among the marine Isojjods soverol are temporary par- ouinmunUxi ^^^^^ adhering to tlie surface of fish ; others are perman- ent parasites, which live in the gill- or body-cavity of other Crustacea, and which con8c({ucntly loose much of their resem- blance to the free Isopods. Of tiio fresh-water Amjdiipods BjKicies of a genus Gammarus (Fig. 124), are everywhere to be met with. The gills are on the thoracic legs, the abdominal legs being partly for swimming, and partly for leaping. Species of an allied genus, Pontiporeiay occur in Rg. »«»«an«8p. x 8. ^^^ ^^reat Lakes; they are inter- esting, like My sis, because the other species are chiefly marine. 14. The lower orders (sepai^ated in a sub-class Entomostraca, from the foregoing Malacostraca,) exhibit by no means the same constancy in the number of segments which we meet with in the* higher, nearly allied forms often presenting considerable differences in this respect. All of the orders except one—the Oirripedia—have fresh-water representatives, which are for the most part inconspicuous, often microscopic, creatures. The most primitive forms, as well as the largest we have to mention, belong to the Phyllopoda, a group in which all the BQgments behind the head bear flat leaf-like swimming-Iega. Please note that these images are extracted from scanned page ima
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Keywords: ., bookcentury1800, bookdecade1880, bookpublishe, booksubjectzoology
