CRUSTACEA 



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Fig. 223. A, Male reproductive organs of Astacus fluviatilis. From Howes. 

 r.t. right anterior lobe of testis ; med.t. median posterior lobe of testis ; vas de. 

 vas deferens; op. external opening of vas deferens; leg, right fourth ambula- 

 tory leg on v^hich the vas deferens opens. B, Female reproductive organs of 

 Astacus fluviatilis . From Howes, r.od. right oviduct : the left oviduct is shown 

 partly opened ; r.ov. right lobe of ovary ; l.ov. left lobe of ovary with the upper 

 half removed to show the ovarian cavity, which is the remains of the coelom 

 and into which the ripe ova drop; op. external opening of oviduct; leg, right 

 second ambulatory leg on which the oviduct opens. 



Fig. 224. A ventral view of the first Nauplius of Cyclops. After Dietrich. 

 an.' antennule; an." antenna; gn. gnathobase; Ibr. labrum; md. mandible. 



