Vol. 3] Torrey. — Biological Studies on Corymorpha. 



257 



deposited at various periods of the day, usually during the early 

 morning hours, many reaching maturity and being discharged 

 at about the same time from the medusae of the same polyp 

 They were heavier than sea-water and sank rapidly, clinging to 

 any object they might touch. Occasionally they underwent 

 several cleavages while adhering to the wall of manubrium or 

 subumbrella, and frequently developed in contact with the base 

 of the stem and the rootlets of the holdfast. Laid naked and in 



Fig. 5. Camera drawings of a single egg during forty-eight minutes. 



X 46. 



large numbers, their amoeboid movements sometimes resulted in 

 the fusion of two to fifteen or more into irregular amoeboid 

 masses which failed to develop. Lots of eggs exhibiting the 

 minimum number of fusions gave the maximum number of de- 

 velopments. 



III. — Segmentation of the Egg; the Embryo. 



For the purposes of this paper, the early development may be 

 considered very briefly. The nucleus of the well grown ovarian 

 egg is eccentric, lying next the thin ectodermic membrane invest- 

 ing the gonad (Fig. 3). Its position does not appear to have 

 any future morphological significance for the individual. Fig. 6 

 represents typically the first four cleavages, beyond which point 

 the behavior of individual blastomeres has not been followed. 

 The first cleavage plane passes across the major axis of the egg, 

 and results in equal blastomeres. The second plane passes at 



