The letters have the same meaning in all the figures. 



aa 



al 



bm 



bp 



ct 



cv 



dk 



da 

 dw 



ea 

 ec 

 ei 

 eo 

 ep 



f 



ffb 

 9° 

 9P 

 9 s 



gy 



gw 

 h 



i 

 it 



Oral opening. 



Oral lobes. 



Adradial marginal lobes. 



Perradial gastral pouches. 



Tentacle canals. 



Velarium canals. 



Cathammal plates (or endodermal lamella? 

 of the septa). 



Endoderm of the umbrella 



Endoderm of the subumbrella. 



Exumbrella (external surface of the um- 

 brella). 



Exradial exumbral furrows. 



Coronal furrow of the exumbrella. 



Interradial exumbral furrows. 



Sense niche of the exumbrella. 



Perradial exumbral furrows. 



Gastral filaments. 



Basal stomach. 



Gastral openings (perradial). 



Palatine stricture. 



Palatine groove. 



Pyloric valves. 



Subumbral wall of the stomach. 



Umbrella cavity. 



Interradial funnel cavities. 



Tentacle funnels (axial cavities). 



ks Cathammal ridges (septa). 



?ni Interradial longitudinal muscles of the 



subumbrella. 

 mp Perradial longitudinal muscles of the 



subumbrella. 

 mw Layer of circular muscles of the subum- 

 brella. 



Khopalia (perradial sense clubs). 



Ectoderm of the subumbrella. 



Nerve ring. 



Leaf-shaped genitalia. 



Germinal epithelium of the endoderm. 



Ova cells. 



Tentacles. 



Umbrella. 



Elastic fibres of the gelatinous umbrella. 



Gelatinous substance of the umbrella cone. 



Gelatinous sockel (pedalia). 



Velarium. 



Erenula velarii. 



Free margin of the velarium. 



Subumbrella (inner surface of the um- 

 brella). 



Mesogonia (mesenteric folds). 

 z Supporting plate (fulcra! lamella). 

 zg Supporting plate of the genitalia. 

 zw Fulcrum of the subumbrella. 



or 



qw 



re 



s 



sd 



so 



t 



u 



»/ 

 ug 

 ui 



va 



vf 



vm 



w 



wr 



Fig. 1. — The entire Medusa profile view, natural size. "We see two sides of the cubical 

 umbrella, which touch at the interradial furrow of the angle (ei). 



Fig. 2. — Perradial section through the umbrella, natural size. On either side we look into an 

 opened radial pouch (bp). The complete middle radial pouch is mostly occupied by the leaf-shaped 

 geuitalia, which project from the interradial septal ridges (ks). 



Fig. 3. — Interradial section through the umbrella, natural size. We see two side walls of the 

 cubical subumbrella, which meet in the septal ridges (ks) in the interradial angles and whose coronal 

 muscle is halved by the perradial band-shaped longitudinal muscle (mp). 



Fig. 4. — Subumbral view of the umbrella, from above (from the apical surface), natural size. In 

 the middle the cross of the perradial gastral grooves (gs) gleams through the quadrate apex. 



Fig. 5. — Subumbral view of the umbrella from below (from the surface of the oral opening) 

 natural size. Through the opening of the velarium (va) in the bottom of the umbrella cavity, we 

 see the bottom of the stomach with its subumbral circular muscles (giu) and perradial gastral grooves 

 (gs) ; in the middle the oral cross with the oral lobes (al). 



Fig. 6. — Transverse section through the umbrella, nearly in the middle of the height, from 

 below, natural size. The four pairs of reproductive leaves (s) are visible in the opened radial pouches 

 (bp) and the four gastral openings (go) in their bases. 



Fig. 7. — A phacellus or bunch of filaments, slightly enlarged, consisting of a group of dendriform 

 gastral filaments, which is placed upon an interradial pylorus valve in an angle of the bottom of the 

 stomach. Below, a piece of the subumbral wall of the pouch (w) and of a cathammal septum (ks). 



Fig. 8. — A quadrant of the velarium with the surrounding parts, seen from the subumbral side, 

 four times the natural size. The velarium (va) with its dendriform canals is fastened by the 

 perradial frenula (if) to the subumbrella (w) and retroverted upwards. The nerve ring (re) rises in 

 an arch from the sense niche (co) to the interradial tentacle pedalium. 



Fig. 9. — The oral cross with the four oral lobes, which are folded and thickly frilled, seen from 

 below, three times the natural size. 



Fig. 10. — Transverse section through a cathammal septum (ks) with the surrounding parts greatly 

 enlarged. "We see that the reproductive leaves run out from the subumbrella, on the axial side of 

 the cathamma. 



