189 
crasped.on region alternated. That is fo say the ciliated streaks 
were mterrupted here and there. Often only one ciliated streak 
was present in the portions of the ciliated streak. In the part of 
mixed character the craspedion region was broad and in the middle 
line somewhat invaginated, in the lower part it agreed with the 
craspedion in Ceriantheopsis americanus (Ca rigren. Ingolf Actini- 
aria. PI. 5. fig. 3). Its longitudinal muscies were very well devel- 
ped. The acontoids were well developed, thick at the base, thin- 
er at the apex. The descending and the ascending limbs were 
;Tovided with comparatively few gland-cells and scattered small 
^irocysts. In the endodermal parts between the limbs there were 
umerous, very large curved nematocysts, besides present in great 
umber m the whole endoderm of the ps-, M- and m mesenteries, 
not in the B- and b-mesenteries. In the textflgures 12 and 13 
have given two figures of the acontoids. The acontoids in Isamch- 
M us thus display a somewhat dilferent structure from that of 
rachnanthus and agree more with those in Ovactis. 
In the greater part of the sectioned piece of Mi, there were 
