REPORT ON THE DEEP-SEA MEDUSAE. 125 



circular folds, in Drymonema both this coronal muscle, and the sixteen broad radial 

 pouches in whose subumbral wall it lies, have undergone such strong retrograde formation 

 that we can only discover faint rudiments of them. On the other hand, the peripheric 

 part of the umbrella corona, with the zone of tentacles and the branched lobe pouches, 

 attains a most extraordinary degree of development. The marginal lobes themselves 

 are fused together, and form a broad marginal border (in some measure a velarium), 

 which is separated from the broad marginal zone, by a deep marginal coronal furrow. 

 The latter occupies nearly the half of the whole subumbrella, and is beset over its whole 

 extent with numerous scattered tentacles. The tentacles are inserted by their basal 

 part in deep radial furrows of the subumbrella, which are separated by its strongly 

 projecting dichotomously branched ribs. The eight sense clubs lie in deep niches of 

 the subumbrella, at the marginal coronal furrow, far from the free umbrella margin, 

 However peculiar these conditions of formation of the subumbrella, and the corresponding 

 modifications of the peripheric vascular system in Drymonema may appear, they are 

 really easily derived from the well known conditions of the Cyanea ; we only require to 

 suppose the eight adradial horseshoe-shaped tentacle areaa, in which the tentacles of 

 the Cyanea are inserted in several rows, the one behind the other, so widely extended 

 that the broad coronal muscle at their proximal margin is reduced to a narrow edging. 

 The sixteen broad radial pouches lying below the coronal muscle become likewise 

 rudimentary, and the numerous tentacles are scattered singly on the wide subumbral 

 surface. On the other hand, the broad marginal lobe zone, whose marginal lobes are 

 fused into a connected velarium, remains free from them. The eight rhophalia, which 

 originally lay freely on the umbrella margin between the sixteen Ephyra lobes, are 

 consequently now placed entirely on the lower surface of the umbrella. 



Drymonema victoria, Hasckel (Pis. XXX., XXXI. ). 



Drymonema dalmatina, Hreckel, 1879, System der Medusen, p. 642, No. 606. 



Umbrella shallow, discoid, four to five times as broad as high. Marginal umbrella 

 border (velarium) very broad, slightly indented, with eight to ten deep exumbral radial 

 furrows, between which eight to ten double lobes of the gelatinous umbrella appear in 

 each octant (between each two sense clubs). Eight sense clubs in the subumbral velar 

 furrow, in deep niches of the subumbrella, at a distance of nearly one-third of the radius 

 of the umbrella, from the umbrella margin. Four perradial oral arms and four interadial 

 curtain-shaped, delicate-membraned, depending reproductive pouches, the former nearly 

 as long as the radius of the umbrella, the latter half as long. Tentacles very long and 

 very numerous (500-600), scattered all over the subumbrella (inside the velar furrow) 

 and inserted in deep radial furrows between strong, straight, dichotomously branched 

 radial ribs of the subumbrella, Only the marginal velar zone and the central area of the 



