Fig. 6. — The entire Medusa from below (subumbral view), natural size. Of the two 

 diameters of the first order (which contain the four perradia) one bes vertically in the figure, 

 the other horizontally. The central part of the figure is occupied by the oesophagus 

 (or buccal stomach), the peripheric part by the subumbral view of the peripheric corona. 

 The four limbs of the central oral cross are formed by the four perradial buccal pouches, 

 between which the four interradial buccal columns with their broad adradial wings come 

 prominently forward (in the diagonals of the figure). These wings are partly covered by 

 the four pair of adradial oral filaments (barbulae), which project centripetally towards the 

 inside, from the inverted (clear) oral margin. The subumbrella of the umbrella corona, 

 which surrounds the clear, almost quadrate oral margin is divided into three zones, of 

 which the inner zone is formed by the deltoid muscles and the genitalia, the middle zone 

 by the coronal muscle, and the outer zone by the lobe corona with its tentacles and 

 rhopalia. The inner zone of the " subumbrella coronaris " shows the lower (oral) halves of 

 the eight horseshoe-shaped adradial genitalia, whilst their upper (above) halves are hidden 

 in pairs in the four interradial funnel cavities, and not visible in the figure. The eight 

 reproductive glands (testes) are separated by eight triangular deltoid muscles (with 

 longitudinal fibres, diverging distalwards) ; the four perradial deltoid muscles (in the 

 vertical and horizontal diameter of fig. 6), are broader but shorter than the four alter- 

 nating interradial deltoid muscles. The middle zone of the " subumbrella coronaris " is 

 entirely occupied by the broad coronal muscle (" musculus coronaris "). It is divided by 

 sixteen subradial peronia (which lie in the raclia of the fourth order) into sixteen quad- 

 rangular coronal plates ; the four interradial or ocular plates (corresponding to the four 

 sense clubs) are considerably narrower than the twelve tentacular coronal plates, four of 

 which lie perradially and four adradially. The outer zone of the "subumbrella coronaris" 

 is formed by sixteen subradial marginal lobes or coronal lobes ; of which the four pair of 

 ocular (exradial) lobes are somewhat larger, and project more than the four pair of ten- 

 tacular (corradial). The twelve strong tentacles are of equal size and divided into four 

 groups, each of which consists of one medial (perradial) and two lateral (adradial) tentacles. 

 An interradial sense club lies between each two groups of tentacles. 



Fig. 7. — A tentacle, four times the natural size, showing the strong axial longitudinal 

 muscle on its inner surface. The abaxial outer surface appears annulated like a worm 

 by numerous transverse strictures. 



