MEDUSA. I. 



bes 1848), Plymouth (Garstang 1893 95, Lebour 1917); it is mentioned in the International Plank- 

 ton Bulletins from the Bristol Channel and the British Channel every year in May and August. 



The present author has seen this species in great quantities during his stay at Plymouth in 

 1914. It was found for the first time on the night between May igth and aoth, 7 miles south of Eddy- 

 stone lighthouse; the individuals were of different sizes, none were fully grown; it was found again 

 on nearly the same spot on the night between May 25th and 26th and further until June nth con- 



Chart VII. Occurrence of Cosmetira pilosella Forbes. O Occurrence according to the literature. 



stantly in large numbers, but still no full-grown specimens. Plankton samples taken nearer the shore 

 in the neighbourhood of Plymouth during the same space of time contained no specimens of this medusa. 

 According to Garstang (189395, pp. 233 ff.) and Lebour (1917, p. 161) it appears at Plymouth 

 in May or June, is one of the most predominant medusae in July and August, and disappears in Sep- 

 tember. At Valencia Harbour it has been found from the end of April until October (Browne 1896, 

 p. 484 and 1900, p. 719; Delap 1905, p. u). Browne has found quite young specimens at Valencia 

 Harbour both in May and in August. Moreover a tiny medusa (with 2 tentacles), found at Plymouth 

 in September 1895, is considered to belong to this species. As mentioned above, I found no full-grown 



