PORALIA RUFESCENS. 45 



Poralia rufescens Vanhoffen. 



Poralia rufescens Vanhoffen, : 02% p. 41, taf. 4, figs. 15, 16. 

 Plate 13, Figs. 1-5. 



Station 4647 ; trawl ; 2005 fathoms to surface ; 1 specimen, about 250 

 mm. in diameter. 



Station 4701 ; 300 fathoms to sui'face ; fragments (about half) of a 

 smaller specimen, about 75 mm. in diameter. 



The larger specimen of the two is much the better preserved, and, 

 although part of the margin, all the tentacles, and nearly the entire mouth 

 parts are destroyed, allows of the description of several very important 

 features, especially with regard to the gonads, canal system, and rhopalia. 



The canal system, as already noted by Vanhoffen (: 02"), is exceedingly 

 simple, but the canals are nearly twice as numerous in the present specimen as 

 in that of the "Valdivia." Forty-one canals arise from the periphery of the 

 circular gastric cavity ; but since two of these anastomose, only forty extend 

 to the margin of the disc (PI. 13, fig. l). They are broad, and for the most part 

 nearly straight, though several of them show short blind branches. Unfor- 

 tunately it is impossible to state certainly the normal number of rhopalia, 

 only five being intact. However, I feel confident that I have been able to 

 determine the positions of twelve such organs (PI. 13, fig. l), and since a 

 considerable space along the margin is destroyed, it is probable that, as in 

 Callinema, there were sixteen. Fortunately, enough of the margin is intact 

 to allow me to trace the outer portions of the canals with some accuracy. 

 Some little distance within the margin these unite (PI. 13, fig. l) to form a 

 continuous ring canal. Distal to the ring canal the intermediate (tentacu- 

 lar?) canals extend out into the marginal lappets and end blindly. The 

 rhopalar canals branch trichotomously, a narrow median branch running into 

 the rhopalium (PI. 13, fig. 5, r. c), while the two lateral branches end blindly. 



It is impossible to give any accurate account of the marginal lappets, but 

 from such portions of the margin as are intact it appears that the latter is 

 deeply incised in the radii of the rhopaha, while between these organs it seems 

 to have a rather wavy outline. 



The rhopalia (PI. 13, figs. 4, 5) very closely resemble the sense organs 

 described by the Hertwigs ('78) for Phacellophora sicitla Haeckel. The sense 

 organ is covered by a prominent scale, beneath which it stands in an almost 



