. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. 426 CRUSTACEA. as the long cylindrical appendage of Cypridina, winch arises In place of the seventh pair of legs, almost on the back of this animal. The nervous system consists of a bilobed cerebral ganglion and a ventral chain with closely approximated pairs of ganglia, which may unite to form a single ganglionic mass. Sense organs.—In addition to the already mentioned olfactory hairs there is a median eye (Gypris, Cy there), composed of two (often separated) halves; or there are, in addit
. Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote. 426 CRUSTACEA. as the long cylindrical appendage of Cypridina, winch arises In place of the seventh pair of legs, almost on the back of this animal. The nervous system consists of a bilobed cerebral ganglion and a ventral chain with closely approximated pairs of ganglia, which may unite to form a single ganglionic mass. Sense organs.—In addition to the already mentioned olfactory hairs there is a median eye (Gypris, Cy there), composed of two (often separated) halves; or there are, in addition to a small unpaired eye, two larger compound and movable lateral eyes (Cypridina). In Halocypris and Cypridina there is a frontal appendage, which probably functions as a sense organ. Alimentary canal.—The mouth, which is frequently (Cypris) armed with toothed lateral bands, leads through a narrow resophagus into a dilated crop-like portion of the alimentary canal. This is followed by a broad and long stomach, provided with two long lateral hepatic tubes, which project into the lamellae of the shell. The anus opens at the base of the abdomen (fig. 337). Of special glands a club-shaped, dilated glandular tube (poison-glands ?) found in Cythere must be mentioned, T- the duct of which opens to FIG. 33/.—Alimentary canal and generative organs of a female Cypris (after W. Zenker). the exterior through a spinous Oc, ossophagus: PF, crop; T* stomach; D, i « ,1 , • intestine; x] liver; Or, ovary; ,W/, adductor appendage f the posterior muscle; R receptaculum; Vu, vulva; Fa, antennse. caudal fork. , , . _, A neart is present in Cypri- dina and Halocypris on the dorsal surface, where the shell is con- nected to the animal. The function of respiration is performed by the whole surface of the body, over which an uninterrupted current of water is maintained by the swinging movements of the leaf-shaped setose branchial appendages. In many Cypridinidw (Asterojye) there is a doubl
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