Fig. 1. — The entire Medusa in profile, twice the natural size, ug Gelatinous 

 substance of the umbrella. I Tentacles, en Peronia. ck Peronial canals, cm Marginal 

 canal, nc Urticating ring of the umbrella margin, bs Internemal genital pouches (lobe 

 pouches), ok Auditory clubs, z Supporting plate, v Velum (hanging loose). 



Fig. 2. — The entire Medusa seen from below with strongly contracted umbrella 

 margin, three times the natural size. Letters as in fig. 1. The four-lobed oral opening 

 (aw) is visible below in the middle, w Subumbrella. 



Fig. 3. — An auditory club greatly enlarged. q Flat sense cells of the ectoderm, 

 z Supporting plate, d Endodermal otolite cells, ol Otolite. oh Auditory hairs, op 

 Auditory pad. og Ganglion acusticum. nc Urticating ring of the umbrella margin. 



Fig. 4. — A peronium (en) with the surrounding parts, seen from outside, eight times 

 the natural size. Letters as in fig;. 1. 



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Fig. 5. — Longitudinal section through a portion of the distal part of a tentacle 

 greatly enlarged, q Ectodermal epithelium ; h its nematocysts. m Longitudinal 

 muscles, z Supporting plates, y Coin -shaped discoid cells of the endodermal axis, ym 

 Thick membranes of the axis, yh Cavity of the axis filled with clear gelatinous 

 substance (?). yp Protoplasmic cord in the axis of the cavity, yn Central cell nucleus. 



Fig. 6. — A portion of the distal part of a tentacle seen from the outside, greatly 

 enlarged. q Ectodermal epithelium ; n its nematocysts. mt Muscular plate (with 

 longitudinal fibres). y?n Septa of the chordal cells of the endodermal axis. 



Fig. 7. — Horizontal section through a peronium (en), with the two adjacent peronial 

 canals (ck), and the surrounding parts of the umbrella, 120 times the natural size. 

 es Peronial furrow of the exumbrella. em Peronial plate, qe Ectodermal epithelium 

 of the exumbrella. ug Gelatinous substance of the umbrella, uf Elastic fibres of the 

 gelatinous substance. ck Peronial canals. du Flat urnbral endodermal epithelium ; 

 dw high subumbral epithelium of the peronial canals. en Urticating skeletal cells 

 of the peronium. ml Peronial muscle (longitudinal fibres). g Supporting plate 

 of the subumbrella. mw Circular muscular layer of the subumbrella. qic Ectodermal 

 epithelium of the subumbrella (comp. PI. XIV. fig. 12). 



