DESCRIPTION OF THE PLATES. 119 



d One of the primary cells cut off. 

 e Nucleus of the primary cell in a state of activity ; 

 it has just thrown off a series of young marked 

 /In the diagram. 

 g g Are several old walls of former growths. 



h Full extremity of primary cell. 



PLATE V. Fig. 22. A small portion of the testicle of Pagurus Bew- 

 hardus magnified, showing the manner in which 

 the caeca hang from the walls of the seminal 

 tube. 



Fig. 23. Small drop of seminal fluid of lobster, showing 

 the secondary cells before the armature had 

 expanded. 



Fig. 24. Small drop of seminal fluid of lobster from vas de- 

 ferens. That part of the figure above a a, as seen 

 under the microscope, presents one dense mass 

 of secondary cells floating down towards >, where 

 a few are seen separate. 



Fig. 25. A coecum from the testicle of Carcinus Mcenas, 

 showing a germinal spot at its apex just being 

 filled with secondary cells. 

 Fig. 26. The germinal spot enlarged. 



REPRODUCTION OF LOST PARTS IN THE CRUSTACEA. 



.- 



PLATE VI. Fig. 1. Represents the raw surface of the proximal or ad- 

 herent portion of the leg of Cancer Pagurus, after 

 the animal has thrown off the distal portion. 

 The figure represents the parts of the natural 

 size, and only a few hours after the separation 

 had taken place. 



Fig. 2. Is a representation of the same part, after the young 

 leg had grown to some size. It will be observed, 

 that the cicatrix, which was formed upon 1lie 

 raw surface a few hours after separation, has 



