388 SYDNEY J. HICKSON. 



EiG. 42. — Section of a mesentery in the early spring, showing a young 

 spermagem {sp.g.). 



Fig. 43. — Section through a spermagem in the autumn, showing a central 

 coagulum and a crowd of densely packed nuclei in a matrix at the periphery. 



Fig. 44. — Section of a portion of the above showing the nuclei more highly 

 magnified. 



Fig. 45. — A series of stages of the final development of the spermatozoa as 

 seen in a preparation of a broken testis in December, a. A ripe spermatozoon. 

 b., c, d. Stages in the formation of the tail. /. A cell containing four nuclei 

 occasionally met with in these preparations. 



Fig. 46. — A lobed diverticulum from an endodermal canal of Alcyonium 

 meeting an ectodermic invagination to form a bud. 



Fig. 47. — A later stage, when the endodermal diverticulum has joined the 

 ectodermal invagination, but the mouth has not broken through. The dorsal 

 mesenterial filaments have been formed. 



Fig. 48. — A still later stage, less highly magnified, when the mouth has 

 been formed. The connection with a neighbouring fully-formed polyp is 

 shown. The tentacles have not yet been developed. 



