17 
ri or part of the zooeciura, whose orifice opens into the bottora of 
the ooecium. The two valves composing the latter can perhaps be 
regarded as corresponding with the two little spines present in the 
other zooecia. 
8) The acanthostegal ooecia, which are only found in two spe¬ 
cies of the genus Electra {E. zostericola and E. amplectens) are 
cavities internally limited by the covering raembrane of the zooecium 
and externally by a cover made up of two rows of hollow spines. 
As to the way in which the eggs get into the ooecium, in 
respect to the epistomial, the peristomial and the valvular ooecia,. 
there can be no doubt that the migration must take place through 
the orifice of the zooecium, which opens directly into the ooecium. 
As the hyperstomial ooecia have their place quite outside the zooe- 
cial Wall in which there is no perforation, here neither can we have 
any doubt that the eggs do pass into the ooecium by this way and 
the same must be the case in Flustridae and Farciminariidae, in 
which the ooecial, and the zooecial cavities are separated by the 
lower membranous half of the ooecium. According to Calvet^), in Cel- 
laria there exists an opening in the calcareous wall between the zooe¬ 
cium and the ooecium. I must however deny the existence of such 
an opening which I have not been able to find even by grinding 
the colonies in several directions. Though we at present only 
know the calcareous parts of those ooecia, previously referred to the 
endozooecial ooecia, it is not probable that there should here exist 
an internal connection between the zooecium and the ooecium, there- 
fore I must suppose that in all Cheilostomata the migration of the 
egg from the zooecium into the ooecium, must take place through 
the orifice. At first glance the supposition may perhaps appear 
/ 
strange that the egg should first pass out through the orifice of 
the zooecium and afterwards enter the ooecium through its outer 
opening, but firstly there is no other way left, and secondly I do not 
think that this passage will be much more difficult than that which 
9 Op. cit. pag. 265, PI. VI, fig, 11. 
vidensk. Medd. fra den naturh. Foren. 1902. 
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