L.M.B.C. MEDUSA. 275 



Plymouth and Port Erin specimens belong to the same 

 species. 



The budding of medusae from the manubrium is not the 

 sole means of reproduction. The sexual method comes 

 on later in life, and the sexes are separated. The asexual 

 method of budding takes place first and is followed by 

 sexual reproduction. 



The same thing occurs in Amphicodon fritillaria, which 

 at first buds off medusae from the base of the tentacles 

 and then usually ceases to reproduce asexually as soon as 

 the sexual cells begin to appear upon the manubrium. 

 It is quite possible that some of the Sarsidae which are 

 now regarded as distinct species on account of their 

 budding off medusae may only be stages of other species 

 which are described as sexual. 



An abnormal specimen of this species was taken in Port 

 Erin Bay on May 10th, 1893. It has six radial canals 

 instead of the normal four. The additional canals run 

 down to two adjacent interradial groups of tentacles, 

 which possess an abnormal number of tentacles, four 

 being present, while in normal specimens the number 

 never exceeds three. The number of tentacles in each 

 group is as follows : — Perradial 3353, Interradial 2441. 

 There are five oral tentacles. Four of these have four 

 clusters of nematocysts, two terminal and two lateral. 

 The other has a single terminal cluster and two lateral 

 clusters. An abnormal number of radial canals is very 

 rare among the Hydroinedusae. 



Distribution. — Norway, Shetland, St. Andrews, Fal- 

 mouth, Plymouth. 



Thaumantias hemisphaerica , (Miiller). 

 Thaumantias punctata, Forbes {9). 

 Clubb reports (7) that T. hemisphaerica was abundant 



