REPORT ON THE DEEP-SEA MEDUSAE. 131 



root proceeds from the four perradial oral pillars. At the root, the thickened, hardened 

 gelatinous lamella of each curtain still forms a very firm, stiff, cartilage-like plate, 

 ecpiilaterally triangular in outline, which represents, in a measure, the peripheric 

 extension of the perradial oral pillar and contains a deep groove on its axial surface, the 

 arm groove or the direct process of a limb of the oral cross. At the distal margin of 

 this triangular cartilaginous plate of the arm root (at the base line of the ecpiilateral 

 triangle) however, the thick cartilaginous mass of the subumbral gelatinous plate 

 suddenly passes into a very thin, delicate, fulcral lamella. This is spread out widely in 

 the form of the powerful arm curtain (aq), which lies in numerous longitudinal folds, like a 

 curtain full of folds, and represents an extremely delicate transparent membrane, whose 

 axial surface is covered by endoderm, and the abaxial surface by ectoderm. The two 

 plates of epithelium touch one another at the curled distal margin of the arm curtains. 

 This margin nearly coincides at the flatly extended curtains with the umbrella margin, so 

 that they can also envelop the whole subumbrella from beneath like a vefl. The total 

 length of the oral arms is therefore nearly ecpaal to the radius of the umbrella. 



The peripheric coronal intestine, which opens with sixteen broad fissures into the 

 peripheric margin of the central stomach in Drymonema, is distinguished strikingly from 

 that of other Cyaneidse by this peculiarity, that the sixteen broad radial pouches of its 

 inner zone are shortened extremely, and appear almost rudimentary, whilst their 

 peripheric ramifications, which correspond to the lobe canals of the other Cyaneidse with 

 their branch canals, are of extraordinary extent ; they here occupy from two-thirds to 

 three-fourths of the whole umbrella, as the radial septa or cathammal ridges advance 

 centripetally between them, nearly to the periphery of the central stomach (comp. fig. 1, 

 quadrant, to the right above). 



The sixteen broad radial pouches, which run out from the periphery of the central 

 stomach, are extremely short and hardly recognisable as independent formations, as they 

 immediately become dichotomised. A stright ocular canal (figs. 3, 4, co) runs from the 

 eight narrower ocular pouches to the eight sense clubs, whflst a pair of narrow ocular lobe 

 pouches run parallel to the two sides of the canal, and dichotomise towards the periphery 

 (fig. 4, cl). The eight adradial tentacular pouches, which alternate with the eight ocular 

 pouches, are much broader, and immediately divided by repeated bifurcations into numerous 

 peripheric branch canals. Whilst these branch canals, or the branched marginal vessels 

 which originally run out from the distal margin of the lobe canals, are usually distinguished 

 in the other Cyaneidaa by their arched course and delicate dendritic side branches, in 

 Drymonema they run in a perfectly straight line and almost parallel, close to each 

 other, only diverging radially a little towards the umbrella margin. Corresponding to 

 this straight course of the narrower, rectdinear branch canals, we have the simple ridge 

 form of the rectilinear radial septa or fused ridges by which they are separated. The 

 eighty narrow, long, marginal pouches, which correspond to the lobes of the broad, 



