Fig. S.—Astacu^fluviatilis.—Yentrsil or sternal views (nat. size). A, male ; B, female :— 

 a, vent ; gg, opening of the green gland ; lb, labnim ; mt, metastoma or lower 

 lip ; od, opening of the oviduct : vd, that of the vas deferens. 1, eye-stalk ; 2, 

 antennule ; 3, antenna : /,, mandible ; 8, second maxillipede ; 9, third or external 

 maxillipede ; 10, forceps ; 11, first leg ; U, fourth leg ; 15, 16, 19, 20, first, second, 

 fifth, and sixth abdominal appendages; x., xi., xiv., sterna of the fourth, fifth, 

 and eighth thoracic somite ; xvi., sternum of the second abdominal somite. In the 

 male, the 9th to the 14th and the IGth to the 19th appendages are removed on 

 the animal's left side : in tlie female, the antenna (with the excepticn of its basal 

 joint) and the 5th to the 14th appendages on the animal's right are removed ; the 

 eggs also are shown attached to the swinimerets of the left side of the body. 



