THE OSTRACODA 



65 



Nervous System. — The supraoesophageal ganglion is largest in 

 the Cypiidinidae in correlation with the presence of paired eyes in 

 that family. The ventral nerve-chain is represented by a single 



Fig. 3S. 

 (■//;i/(''/i/i«( iiiedUerrinua. Fnnalo (al)ovp) anil nialo (Ih-Iow). One valvo of sliell removed to 

 show aiipenrlages an<l internal organs. A", antenna (the antennule is just above) ; F' (below), 

 fciiirth post-oral limb ; F' (above), lifth post-oral limb ; Fu, cauflal furca ; G, brain ; //, heart ; 

 M, mid-^'vit; MJf, mandibular palp; Mx', maxillula; Mx", third jiost-oral limb (maxilla); 0, 

 jiaired eye ; (/, median eye ; P, ])enis ; .s'..l/, ailductor muscle of shell ; .St:, frontal tentacle ; 7', 

 testis. (I'roin Claus's TiXthuok.) 



