Fig. 1. — The entire Medusa, seen from the side and somewhat from below, four times 

 the natural size. The eighteen tentacles are retroverted upwards. The lobes of the 

 umbrella collar are delicately bordered with otoporpas and auditory clubs, below which 

 the velum projects freely. 



Fig. 2. — Exumbral view of a collar lobe (from outside) with an adjacent tentacle (t) 

 ten times the natural size, er Longitudinal ribs of the exumbrella. oo Otoporpse. 

 ok Auditory club, nc Urticating ring of the umbrella margin, v Velum, tr Tentacle 

 root, nb Urticating swelling at the tentacle base, nt Urticating streaks on the abaxial 

 surface of the tentacle. 



Fig. 3. — Subumbral view of a collar lobe (from inside) with an adjacent tentacle (t), 

 ten times the natural size. The folded testis sac (s) hangs freely in the middle in the lobe 

 cavity (hi), sc Opening of the cavity of the spermarium into the periphery of the 

 stomach, go opening of the festoon canal (cf) into the periphery of the stomach, tr 

 Tentacle root, rib Urticating swelling at the base of the tentacle, yn Chain of nuclei 

 of the chordal cells of the endodermal axis, xn Urticating epithelium of the ectoderm. 



Fig. 4. — An auditory club (ok) with its otoporpa (oo) greatly enlarged, q Ectoderm. 

 oh Auditory hair of the ectoderm, d Endoderm. 61 Otolites of the endoderm. op 

 Auditory pad (sense knob), nc Urticating ring of the umbrella margin, e Exumbrella. 

 n Urticating cells, z Supporting lamella. 



Fig. 5. — Horizontal transverse section through a testis sac, su Subumbral ecto- 

 dermal epithelium, zs Supporting fibres containing nuclei, of the testis, sz Mature 

 spermatozoa (zoospermia). sm Mother cells of the spermatozoa (male nuclear cells). 

 z Supporting plate or fulcral lamella, sd Endodermal epithelium of the cavity of the 

 genital sac (sc). 



Fig. 6. — A small piece of the same section of the testis (fig. 5) greatly enlarged. 

 Letters as in fig. 5. 



