176 SIDNEY F. HARMER. 



C. aculeata. — A large proportion of the specimens found 

 at Roscoff in June possessed numerous ovicells. At Plymouth 

 ovicells were also found in April and May. The breeding 

 season is probably much the same as in the last species. 



C. denticulata. — The only specimens obtained in which 

 ovicells were common were found in Guernsey and Jersey in 

 the summer (June to August), which may probably be regarded 

 as the period at which the breeding season is at its height. 



C. cornuta. — The ovicells appear to be commonest in 

 April and May. 



C. geniculata. — The only specimens in which I have found 

 ovicells were obtained in the summer (June to August). I 

 have not found this species at Plymouth. 



