38 GL O. Sars. 



Explanation of the Plates. 



Plate 1. 

 (All the figures drawn from fresh specimens). 



Fig. 1. Oosphère with enclosed, still unsegmented ovum r 



viewed from the lower pole; magnified 68 diameters. 

 » 2. Same oosphère, lateral view. 

 » 3. Spermatosphere with enclosed spermatocyst and 



2 ejaculatory ducts, lateral view; same amplifi- 

 cation. 

 » 3 a. An ejaculatory duct, with its basal cup-shaped 



piece, lateral view. 

 » 3b. Another ejaculatory duct, with the base of the 



cup-shaped piece turned to the observer. 

 » 4. Ovum just after the first cleavage is finished. 



(The external envelope in this and the succeeding 



figures is omitted). 

 » 5. Ovum with 3 cleavage-spheres, one of the primary 



segments having been divided, whereas the other 



still remains undivided. 

 » 6. Ovum with 7 cleavage-spheres; (the large cell in 



the middle appears to be entodermal in character). 



