10 



DR. TH. MORTENSEN. 



half a million. Taking, however, into consideration the decreasing 

 size of the ovaries towards the point of the arm it may be just to 

 take as the mean number of eggs per ovary only 100,000, and 

 for safety we may still reduce the number of ovaries to 2,000. This gives 

 as the number of eggs in a grown female of L. ciliaris no less than 200 

 millions. We might expect from this that this species would be exceed- 

 ingly common, the larvae as well as the grown. But the larvae are only 

 rarely observed, and as for the grown specimens, one may certainly 

 expect to get about half a dozen specimens in each haul with the trawl, 

 and from their large size this makes the impression of a good lot — in 



Fig. 12. 



Fig. 12. — Female Luidia ciliaris, opened so as to show the genital organs, 

 size. (From a photograph by !Mr. F. Martin Duncan.) 



li of natural 



reahty this is a very small number, especially compared with Ophiocoma 

 and Ophiothrix, which are generally taken by thousands in each haul. 

 A\Tiat a waste of eggs must here take place ! 



In Figure 12 is represented a female of L. ciliaris opened so as to show 

 the gonads. It gives, however, only a slight impression of the profusion 

 of gonads seen in such a specimen, the more conspicuous on account of 

 the beautiful red colour of the gonads with the ripe eggs. 



I may here mention that in this species a distinct sexual dimorphism 

 mav be observed, at least in the breeding season. The colour of the 



