182 THE MEDUSAE. 



Gonads. — The gonad is in the form of a ring completely surrounding the 

 manubrium, which it clothes from its base almost to the lip. 



Color. — This Medusa is most brilliantly pigmented. Near the base of 

 the manubrium there are eight adradial groups of vermilion and yellow 

 pigment granules ; the entoderm of the tentacles is vermilion, surmounted 

 by a spot of ochre yellow ; the ocelli are black ; the ectoderm of the ten- 

 tacles and of the manubrium is milky white. This scheme of coloration is 

 constant in all six specimens. 



Sarsia resplendens is related, by the shortness of its manubrium and its 

 total lack of apical canal, to *S'. brachygaster Gronberg ('98), S. flammea 

 Linko (: 00), and S. angulation Mayer (: 00 a ), species which Hartlaub (:07) 

 suggests should be grouped together in a new genus distinguished from 

 typical Sarsia by these two characters ; but from these, as well as from 

 all other species of Sarsia, it is sufficiently well distinguished by the 

 shortness of its tentacles, by the small number of tentacular nematocyst 

 pads, and by the brilliant and characteristic pigmentation. 



Purena Hartlaub, 1907. 



Codonidae with gonads in the form of separate rings surrounding the 

 manubrium; long tentacles set with nettle swellings (not rings). 



The necessity for a new genus to include those species of Sarsia and of 

 Dipurena which are separated from typical representatives of Sarsia by 

 having the gonads in the form of separate rings, and from Slabberia and 

 Dipurena by the long tentacles set throughout most of their length with 

 nettle swellings, was indicated by Browne (:05 b ). It was to fill this 

 want that Hartlaub (: 07) has proposed the genus Purena. 



The numerous examples of this genus in the present collection all 

 belong to one species identical with the Dipurena sp. ? described from 

 Ceylon by Browne (:05 b ), to whose excellent account and figures 

 there is but little to add. Browne was unable to find any constant 

 character to separate this species from the European Sarsia strangulata 

 All man [Dipurena ophiogaster Haeckel), and has given it no specific name. 

 There seem, however, to be certain differences in the form of the gonads, 

 which in the Indo-Pacific form are cylindrical rather than ovate, and in 

 the length of the manubrium, which is much shorter in the Indo-Pacific 

 form than in most of the figures of »S'. strangulata. Inasmuch as these 



