78 THE MODE OF REPRODUCTION OF, &e. 



as we found it in the Brachyura, it is quite extended, although 

 apparently enclosed in a sac. 



As far as my observations have yet gone, it appears to me 

 that the germinal cell is derived from one of those which are 

 nearest the central opening on the raw surface. This cell, 

 following the ordinary course of developement, by the nucleus 

 breaking up into nucleoli, which in time become parent cells, 

 each of which again undergo the same process. This proceeds 

 for several stages, all the less important cells dissolving and 

 serving as nourishment to the central or more important ones, 

 until the number of centres are reduced to five, the number of 

 joints required, which, by a constant process of a similar nature, 

 assume the form of the future leg. 



H. D. S. G. 



