.^^\; 



stk. 



Fig. 249. 



\ 



op. 

 Fig. 250. 



Fig. 249. A specimen of the shore crab (Carcinus) bearing a Sacculina. op. 

 mantle opening; Sac. Sacculina) stk. stalk. 



Fig. 250. A vertical section of Sacculina at right angles to the plane of 

 greatest breadth. From Caiman, at. atrium of oviduct; ga. ganglion; ^/. col- 

 leteric gland opening into atrium; o. eggs in mantle cavity; op. opening of 

 mantle cavity; oz;. ovary ; r?. roots ; stk. stalk; t. testis. 



Fig. 251. An abdominal limb of the prawn Synalpheus infested by Thomp- 

 sonia, x 120. From Potts, bl. blind branch of root system which after 

 further development will become an external sac; en. endopodite of limb of 

 host; ex. exopodite of the same; mtl. mantle of sac; stk. stalk; vm. visceral 

 mass, occupied entirely by the ovary. 



