215 
what longer than the inner, which are often broader at the base 
than the outer. Probably there is no great difference in the size 
of the tentacles in extended State. . The oral disc is very wide, 
hardly one third of it is provided with tentacles. It is deeply sul- 
cated, the furrows correspond to the insertions of the mesenteries. 
The long actinopharynx is furnished with numerous longitudinal 
ridges and two broad siphonoglyphes, the aboral prolongations of 
which are well developed. 
19 
Figs. 18, 19. Isocradactis magna. Fig. 18. Pari of the upper body-wall with simple and 
composed verrucae (“fronds”). Fig. 19. Transverse section of sphincter. Tentacle-side 
• on the left. 
Anatomical description. The ectoderm of the column is 
high and contains few nematocysts 12—14 xi fi, The warts are 
structured as in Urticina felina and there are no nematocysts in 
their apex. The mesogloea is thick, fibrillar and provided with rather 
numerous, small protoplasma-poor cells, in the warts the mesogloea 
is thinner. The endoderm of the column is pigmented, especially 
in the region of the fronds, in the tentacles and oral disc. The 
circular muscies are well developed between the large warts as in 
Urticina, weak in the warts, the fronds-region shows a considerably 
weaker musculature than in other parts of the column. The sphincter 
is diffuse (textfig. 19), elongated and rather well developed, but in 
