28 THE MEDUSAE. 



This genus was founded by Vanhoffen (: 02% p. 27) for a new Medusa taken 

 by the "Valdivia" in the Indian Ocean. Unfortunately the single speci- 

 men was so fragmentary that although it showed the most important generic 

 character, i. e. the number of marginal organs, and its close structural affin- 

 ity to Periphylla, it did not allow of any detailed description. Undoubtedly 

 belonging to this same genus is a specimen in the present collection which 

 is in sufficiently good condition for me to add considerable to Vanhoffen's 

 account. It is impossible to be confident of the specific relationship of the 

 " Valdivia " to the '' Albatross " specimen, because of the poor condition of 

 the former ; yet, since the few differences between the two can easily be 

 explained as due to differences in preservation, I identify the present speci- 

 men as Vanhoffen's species. 



Periphyllopsis braueri Vanhoffen. 



PeriphyUopsls braueri Vanhoffen, : 02", p. 27, taf. 2, fig. 7. 



Plate 9, Fig. 1; Plate 12, Fig. 1. 



Station 4652; 400 fathoms to surface; one specimen, 60 mm. in diameter 

 by 25 mm. high. 



The single specimen is fairly well preserved, but a large part of the 

 stomach and several of the marginal lappets are torn away, while all of the 

 sense organs are battered. 



The bell is flattened, so that at first glance the specimen, like the " Val- 

 divia" example, resembles an Atolla rather than a Periphylla. But in the 

 present case this condition is apparently normal, instead of being the result 

 of imperfect preservation, as Vanhoffen believed. The ring furrow is deep, 

 the pedalia are prominent, and all, both tentacular and rhopalar, of the same 

 breadth. The central disc is about 50 mm. in diameter, its gelatinous sub- 

 stance thick, and its exumbrellar surface smooth. As stated above, there are 

 twenty tentacles, arranged in four groups of five each, each group alternating 

 with a rhopalium. Alternating with rhopalia and tentacles are twenty-four 

 ovate marginal lappets. The radial arrangement of the different series of 

 organs is the same as in Periphylla, each rhopalium lying in the radius of 

 the centre of one of the sides of the stomach, being thus interradial, while 

 the central one of each group of five tentacles is perradial, lying in the 

 radius of one of the gastric ostia (PI. 21, fig. l). 



The tentacles are about as long as the bell-diameter, and taper gradually 

 from base to tip (PI. 9, fig. 1). The sense organs are all so much damaged 

 that I can give no description of their structure. 



