118 DESCRIPTION OF THE PLATES. 



that between b b is the dilated or gastric. The 

 vasa deferentia are not seen in this species so 

 well as in Hyas araneus, Fig. 8, c c. It is in the 

 gastric division that the pabulum lies in such 

 quantities. 



PLATE IV. Fig. 7. Is the internal or sheathed portion of the external 

 organs of Cancer Pagurus ; proximal extre- 

 mity. 



Fig. 8. Testes of Hyas araneus. a a Tubular portion, b b 

 Follicular portion, c c Vasa deferentia. 



Fig. 9. External organs of Cancer Pagurus. a Is the in- 

 ternal or sheathed portion in situ. b Is the 

 sheath or external portion. 



Fig. 10. External organs of Hyas araneus. A Sheath. B 



Sheathed portion. 



PLATE V. Fig. 1 . First stage of developement of secondary seminal 

 cell of Galathea strigosa. 



Figs. 2, 3, 4, Second, third, and fourth stages of develope- 

 ment of the secondary cell. 



Figs. 5, 6, 7, 8, 9, 10, 11, 12, 13, Various stages of deve- 

 lopement of the secondary cell of lobster. 



Figs. 14, 15, 16, 17, The same treated with acetic acid. 



Fig. 18. Tertiary or spermatozoal cells. 



Fig. 19. Secondary cell of lobster seen from armed extre- 

 mity, to show the three setae. 



Fig. 20. Primary cell, or coecum of testicle of Pagurus 

 Bernhardus full of secondary cells, c Attachment, 

 b Free extremity, a Nucleus. 



Fig. 21. Primary seminal cell of Pagurus Bernhardus fill- 

 ing with secondary cells. As already described, 

 these cells grow in pairs from discs on the walls 

 of the seminal tubes, and hang free in the cavity 

 of the tube. It has also been described how the 

 secondary cells are produced from the parent 

 nucleus, namely, by means of successive growths, 

 each of which carries off a fold of the nucleus 

 before it. 



a Disc from which the primary seminal cells grow. 

 b b The discs on each side of it. 

 c c The origins of the primary seminal cell?. 



