Fig. 1. — The entire Medusa, from above, spread out flat (exumbral view), eight times the natural 

 size. The inner half of the central umbrella disk is undivided, the outer half is divided into sixteen 

 subradial swellings. The peripheric umbrella is divided by sixteen deep subradial furrows into six- 

 teen gelatinous six-kels or pedalia, of which the eight narrower (principal) bear the sense clubs, the 

 eight broad (adradial) bear the tentacle. 



Figs. 2-10. — Horizontal transverse section at different heights, indicated in fig. 14. (PI. XXVIII.) 

 by the numbers II. — X. The gelatinous substance or supporting plate of the umbrella is invariably 

 coloured blue, the ovaries red, and the hollow space of the gastrovascular system yellow ; eight times 

 the natural size. From want of room only half of the sections are given, h Umbrella cavity, i 

 Funnel cavity, st Supporting plate of the ovaries (sterigma). so Egg cells, bo Ocular pouches. 

 bt .Tentacle pouches, tip Endodermal folds of the subumbral wall of the ocular pouches, mc Coronal 

 muscle, w Subumbrella. gb Basal stomach, gc Central stomach, go Buccal stomach. 



Fig. 2. — Transverse section through the basal stomach immediately above the septal nodes, at the 

 height of the pyloric valves (gi). f Gastral filaments. 



Fig. 3. — Transverse section through the central stomach at the height of the interradial cathamma 

 or septal nodes (Ten) ; the four broad horizontal gastral openings of the four perradial gastral pouches 

 (bp) alternate with these, ii Interradial funnel cavities. 



Fig. 4. — Transverse section through the coronal intestine, immediately below the coronal sinus, 

 through the uppermost (proximal) part of the genitalia (s). Four broad interradial pouches (bi; 2 ) 

 alternate with four narrow perradial ocular pouches (boj from which, but somewhat deeper, the four 

 interradial ocular pouches (bo 2 ) and the eight adradial tentacle pouches (bt) run out. Comp. fig. 5. 



Fig. 5. — Transverse section through the coronal intestine, somewhat lower than the preceding. 

 The eight wide adradial tentacle pouches (bt) containing the genitalia (s), alternate with the eight 

 narrow ocular pouches (bo) and project, as if inflated, into the umbrella cavity (h). The supporting 

 plates (st) of the two genitalia belonging to one pair, are. rolled inwards so that their concavities are 

 opposite one another. 



Fig. 6.— Transverse section through the coronal intestine, somewhat above the coronal muscle. 

 The supporting plate of the genitalia (sterigma st) springs from the subumbral wall of the eight 

 adradial pouches (bt), apparently with a double root, as the simple root is crescentic and cut out 

 concavely above (the section touches both horns of the crescent, comp. fig. 7). 



Fig. 7. — Transverse section through the coronal intestine, somewhat below the proximal margin 

 of the coronal muscle (mc). The supporting plate of the genitalia (sterigma, st) springs with a 

 simple root from the subumbral wall of the coronal muscle (mc). Of the eight ocular pouches only 

 the four perradial are furnished with subumbral endodermal tufts. 



Fig. 8. — Transverse section through the coronal intestine in the lower third of the coronal intestine 

 (mc). All the eight ocular pouches (be) are furnished with endodermal tufts. The section is taken 

 obliquely so that the four pairs of tentacles, from above to below, correspond to four different heights 

 or horizontal planes, lying one above the other. The distal ends of the genitalia are still visible in 

 the two upper tentacle pouches (A, B) but not in the two lower (C, D). 



Fig. 9. — Transverse section through the lobe corona at the base of the tentacle insertion. This 

 section is also taken somewhat obliquely at four different heights (A-D). 



Fig. 10 — Transverse section through a sense club and the surronndiug sense lobes (lo). 



Fig. 11. — Transverse section through an ovary thirty times the natural size, w Subumbrella. 

 st Supporting plate of the ovary (sterigma). st^ Boot of the sterigma. so Egg cells, ds Germinal 

 epithelium of the endoderm. dw Subumbral endodermal epithelium on the free upper surface of 

 the ovaries, ss Genital sinus. 



