232 University of California Publications in Zoology. [Vol. 6 



the masses of cells or buds which are destined to make both the 

 future polypides and the contents of ovicells. At certain early 

 stages these are indistinguishable, (:03), but later some 

 of these masses of cells change into polypides. others surround an 

 ovum and become inclosed by an ovicell. Just what the impulse 

 is which causes the bud in one case to transform into an ordinary 

 polypide, and in the other into a nutritive follicle surrounding 

 a developing ovum, is not known. 



KEY TO THE SPECIES OF CRISIA. 



1. Zoceeia typically uniserial 2 



1. Zoceeia biserial 5 



2. Ocecia concave on the ventral side 3 



2. Ooecia not concave 4 



3. Ooeciostome opening on the dorsal side of the ocecium below the 



summit; oceciopore circular, directed somewhat backward and 



upward Crisia edwardsiana. 



3. Ooeciostome opening on the ventral side of the ocecium at the 



summit; oceciopore circular, directed somewhat backward and 



upward Crisia iranciscana. 



; Ooeciostome opening at the summit of the ocecium. tube curved 



forward; oceciopore elongated, slit-like and opening ventrally; 



or circular and opening upward Crisia geniculata. 



5. Ocecial internode possessing two, three, or more branches, one 



of which occurs just above the summit of the ocecium 7 



5. i Icecial internode not possessing more than three branches, and 



never possessing one at the summit, of the ocecium 6 



6. Oo?eiostome covered by a cap or operculum .. Crisia operculata. 



6. Ooeciostome not covered by a cap or operculum 7 



7. Tube of ooeciostome bent forward 8 



7. Tube of ooeciostonie not bent 9 



8. Tube of ooeciostome short; oceciopore flattened from right to 



left Crisia pacifica. 



S. Tube of ooeciostome long, either flattened or circular 



Crisia pugeti. 



9. Ooeciostome opening slightly dorsally behind the summit of the 



ocecium, its tube short and of the same diameter throughout; 



oceciopore opening upward Crisia occidentalis. 



9. Ooeciostome opening slightly dorsally behind the summit of the 

 ooecium, its tube short, wider below than above; oceciopore 



(■pining not directly upward but inclining ventrally 



Crisia maxima. 



