NARCOMEDTJS.E — SOLMARIS. 



435 



and the same time, giving rise to a 16-cell stage. In any event, the cells of the upper (animal) 

 pole usually divide so as to become smaller than those of the lower. No segmentation cavity is 

 formed; but the superficial cells divide one after another and their inner-halves migrate 

 inward to form a loose mass of cells which gives rise to the entoderm. The planula becomes 

 oval in outline. The gallert forms a cap-like mass of gelatinous substance between the ecto- 

 derm and entoderm at the upper end of the larva. The exumbrella entoderm cells are small 



Fig 28 t —Solmaris fiavescens, from life, by the author, at Naples Zoological Station, winter of 1907-08. A. Side view of mature 

 ' medusa. B. Immature sensory-club. C. Fully-developed sensory-club. D. Tentacle. E. Stomach-margin show- 

 ing female gonad. F. Diagrammatic section of medusa. 



and flat while those of the subumbrella entoderm are very high and large. The tentacles grow 

 out as wide basal bulbs from the margin and finally the bell grows out as a ring beneath and 

 between the tentacle-bulbs. The mouth breaks through and the medusa is thus formed from 



the actinula. . . 



The origination of the primitive, entoderm cells through division from the inner ends ot 

 the superficial cells of the blastula recalls the condition observed in Liriope. 



