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THE MICROPLANKTON OF PLYMOUTH SOUND. 16] 
ANTHOMEDUS&. 
“ The Meduse of the World,” Mayer. 
Steenstrupia rubra Forbes. Begins in April and is common till the 
middle of June when it disappears. 
Hybocodon prolifer L. Ag. Begins at the end of March, is common 
through April, very common in May up to the middle, then 
dwindles and disappears in the beginning of June. 
Sarsia prolifera Forbes. Rare, in June only. 
S. tuberosa Lesson. Once only in June. 
S. eximia Allman. Once only in September. 
Slabberia halterata Forbes. Once only early in September. 
Stomotoca dinema L. Ag. Begins in July, is common through the 
month, becomes less common and disappears in November. 
Turris pileata (Haeckel). Fairly common now and then in June, 
July and August, rare in September and October. 
Bougainvillia brittanica Forbes. Once only in June. 
Rathkea octopunctata Haeckel. Begins in the middle of February, 
one of the first ineduse to appear, becomes very common in April 
and the beginning of May, disappears in the middle of June. It, 
however, reappears in September as a single specimen. 
Willsia stella‘a } orbes. Once only at the end of August. 
LEPTOMEDUS2. 
Obelia sp. Meduse extremely abundant. Begins at the end of 
February, very common from May to October, leaves off at the 
end of November and is absent through December, January and 
most of February. 
Cosmetira pilosella Forbes. Begins in May, very common on and 
off from June to September. 
Clytia volubilis Lamouroux. Once only in April. 
Phialidium hemisphericum (Gron.). Perhaps the commonest of the 
meduse here. Begins at the end of January, is common from May 
to October and continues till the middle of November. 
Saphenia gracilis Forbes and Goods. Rare in May. On June 14th 
the nets were full of it and it was abundant once in August. 
