386 CRUSTACEA ENTOMOSTRACA. 



in the Cypridae are directed upwards over the hind part of the 

 body and beneath the shell. In both families they probably 

 have the function of keeping the hinder part of the interior 

 of the shell clean (Putzfuss). In the Halocypridae these ap- 

 pendages are represented by long slender flagella. 



A pair of short and stalked " brush-shaped organs " with 

 sensory functions, which are present in the males of the Podocopa , 

 are regarded by Miiller as the representatives of an eighth pair 

 of appendages. In the Cypridae and Cytherellidae they lie 

 behind the seventh, but in other Podocopa they are situated 

 in front of them. In the Cypridinidae they probably enter 

 into the formation of the penis (Fig. 2516, P). 



The nervous system consists of a bilobed cerebral ganglion and 

 a ventral chain with closely approximated pairs of ganglia. A 

 suboesophageal mass supplies nerves to the mandibles and first 

 maxillae. 



Sense organs. In addition to the olfactory hairs and " brush- 

 shaped organs " already mentioned eyes are generally present. 

 Except in the Halocypridae the unpaired or nauplius eye is 

 present, consisting of a ventral median and two lateral elements 

 which may be united in the middle line or, as in some Cope- 

 pods, quite distinct. 



In the Cypridinidae (Fig. 254, 0) there is in addition a pair of 

 compound lateral eyes consisting of a number (4-50 or more) 



of separate elements. The 

 Halocypridae and Poly- 

 copidae are without eyes. 

 In the Cyprinidae a peculiar 

 median, rod-shaped organ, 

 the frontal process (Stz) pro- 

 jects forward, in theneigh- 

 bourhood of the nauplius 



FIG. 255. Alimentary canal and generative organs 



of a female Cypris (from Claus, after W. Zenker). ^y^- 



D intestine. The opening of the anus, which Aliv/\*o7 ni TI 



is not seen here, is dorsal to the caudal fork. Fu Alimeniary Canal. 



2ieSSr? ; sM mouth, which is frequently 

 (Cypris) armed with 



toothed lateral bands, leads through a narrow oesophagus 

 into a dilated crop-like portion of the alimentary canal (Fig. 

 255), which in Bairdia is developed into a regular mastica- 

 tory mill. This is followed by a broad and long stomach pro- 



