Fig. 1. — The entire Medusa, exumbral view (from above) ; painted by me from life in 

 Pola, twenty times the natural size. The eight principal ribs (four perradial and four 

 interradial) of the sixteen projecting radial ribs of the exumbrella are distinguished by 

 blood-red pigment, accumulated, like an ocellus, at the distal end, whilst the eight 

 adradial ribs, alternating with them only show the same black pigment (yellow white in 

 reflected light) as the festoon-shaped urticating band of the exumbrella, running parallel 

 to the umbrella margin. In the middle the golden-yellow base of the stomach with the 

 surrounding corona of red genitalia shines through the umbrella. The numerous sucking 

 tentacles are divided into sixteen bunches on the umbrella margin. 



o 



Fig. 2. — Umbrella (without tentacles) subumbral view (from below) with strongly 

 contracted oesophagus ten times the natural size. The velum is omitted, as Oral 

 cross, al Oral lobes, s Genitalia, wr Mesogonia. w Subumbrella. Im .Marginal 

 lobes, oh Auditory club. 



Fig. 3. — Umbrella (without tentacles) subumbral view (from below) with widely 

 extended oesophagus, ten times the natural size, am The octagonal margin of the flatlv 

 extended oral disc, through whose thin wall both the genitalia (s) and the free margin 

 of the velum (vm) shines, g Central gastral cavity, ok Auditory club. 



Fig. 4. — Transverse section through a hollow sucking tentacle (or "ambulacral foot") 

 greatly enlarged. qt Ectoderm, zt Fulcral plate. dt Endoderm (flagellate cells). 

 ct Axial canal of the tentacle. 



Fig. 5. — Tangential transverse section through a genitabum, fifty times the natural 

 size. e Exumbrella. vg Gelatinous umbrella. w Subumbrella. cr Eadial canal. 

 se Reproductive pouch, d Endodennal epithebum of the pouch, z Fulcral plate. 

 sra Spermarium. sw Subumbral ectodermal epithebum of the testis, wr Transverse 

 section of the mesogonium. 



