. A manual of zoology. Zoology. 374 ARTllROPODA Order II. Balanids. Sessile cirripeds with calcareous shell formed of carina, roslrum, and Urer- alia; scnia and ieri;a ,' the \-alves vfii;. 300). Bjldiiiis,'^ Coroiiiilj. allached to whales. Order III. Rhizocephala. These differ sjreatly from other cirripeds. They are parasitic on the abdo- mens of decapod cral'S and consist of a stalk which penetrates the body of the host and a liodv which remains outside i,U^'. J04l- The stalk branches in a root-like manner, penetrates the cephalothorax and absorbs its juices. Since the stalk furnishe
. A manual of zoology. Zoology. 374 ARTllROPODA Order II. Balanids. Sessile cirripeds with calcareous shell formed of carina, roslrum, and Urer- alia; scnia and ieri;a ,' the \-alves vfii;. 300). Bjldiiiis,'^ Coroiiiilj. allached to whales. Order III. Rhizocephala. These differ sjreatly from other cirripeds. They are parasitic on the abdo- mens of decapod cral'S and consist of a stalk which penetrates the body of the host and a liodv which remains outside i,U^'. J04l- The stalk branches in a root-like manner, penetrates the cephalothorax and absorbs its juices. Since the stalk furnishes the food, an alimentary canal is absent. The body lacks all appendages, is enclosed bv a soft-skinned mantle, and is almost entirely. Fig. tQ4.—Sdcc'ulina cjrciui attaelicd to Civc'nnis niann^, whose abdomen {^T) is ex- tended. HI, se.\ opening of Sjcciilina; r, network of roots ramifying the crab; .'.'. stalk. filled with the gonads. Since the adult ]iarasites lack all arthropodan features, their position is onlv settled by their development (tig. ^o^b which is like that of other cirripeds. These forms are rare on the .Vmericaii coast. Suicnliiio, Piilo;^iislcr.* Two more orders, .-\RDO>[IX.\ and ., parasitic in the mantle and shells of molluscs and other cirripeds, scarcely need mention. Sub Class I'. Mahn'oslrdi'a. The ]\Ialacostraca arc sharply marked otT from the other Crustacea by having a l.)otly wliich consists of twcittv segments, of wlijch seven, are abdominal (Xclhilia has twenty-one, eight abdomiital). The orgaits are represented by the antennal glands, and shell glaitds are lacking except in the larvtv and some Isopoda. The male genital ducts open on the tliirteenth, the female on the eleventh, 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 Hertwig, Richar
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
