192 



Papers from the Department of Marine Biology. 



The arm disk is half as wide as the bell, and the subgenital portions is 

 unitary. The external faces of the perradial columns have each a slight con- 

 cavity, not a deep niche, as in Lychnorhiza bartschi. The subgenital ostia are 

 twice as wide as the perradial columns and each is arched over by a flap-like 

 projection. There are also 4 interradial papillse upon the subumbrella, one 

 opposite the opening of each subgenital ostium. 



The 8 mouth-arms are not quite two-thirds as long as the bell-diameter, 

 the upper arms being not quite half as long as the lower arms. Each mouth- 



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FIG. 6. Lychnorhiza bornensis, from Tawao, Borneo, September 30, 1909. Natural size. The 

 gastro-vascular canals are shown in one-third of the subumbrella. 5 arms are removed, 

 being cut off close to the arm-disk. 



arm terminates in a single, slender, tapering, thread-like filament about 50 mm. 

 long. There are also a few shorter, more slender, filaments which arise from 

 the sides of the mouth-arms between the mouths. There are no filaments 

 upon the arm-disk. 



There is a wide zone of circular muscles in the subumbrella, and these are 

 only partially interrupted in the 8 rhopalar radii. 



The central stomach gives rise to 16 radial-canals, 8 of which extend to the 

 rhopalia and the 8 others end in the ring-canal. On its inner side the ring- 

 canal gives rise to 16X4 radial-vessels, which do not reach the margin of 

 the stomach but anastomose one with another and with the 16 chief radial- 



