BROOKS AND RITTENHOUSE: ON TURRITOPSIS. 437 
Callitiara: Tentacles numerous, in two alternating rows, one 
row without ocelli, and the other with two ocelli on each tentacular 
bulb; lips simple; gonads slightly split in perradii; proximal regions 
of radiating canals with chorda-like endodermal cells. 
Mccradia gen. nov. (Modeeria in part). Tentacles numerous, in 
one row, with a single ocellus on velar side of each tentacular bulb; 
oral lips branched once dichotomously, perradial gonads slightly split 
in perradii; proximal regions of radial canals with chorda-like endo- 
derm. 
Part 3. Embryology of Turritopsis nutricula. 
By Samuel Rittenhouse 
Introduction. 
Work on the embryology of Turritopsis nutricula was begun at the 
suggestion of Professor Brooks. The material was collected and the 
observations on the living specimens were made during the summers 
of 1903 and 1904, while I occupied a table at the United States fish¬ 
eries laboratory at Beaufort, North Carolina. Turritopsis is one of 
the most common medusae in the harbor during the summer. In the 
two years that I was there they became abundant in the beginning of 
July and remained more or less plentiful until I left Beaufort Septem¬ 
ber 13th. While the medusae could be collected in fairly large num¬ 
bers, many of them were immature. They lay only a limited number 
of eggs. Material was preserved and sectioned, however, for the 
study of such facts as could not be made out from the living forms. 
The work was finished in the Biological laboratory of the Johns 
Hopkins university. 
Development of the Ovarian Egg. 
The ova develop in the ectodermal layer of the manubrium. The 
epithelium becomes very much thickened in four regions; these en¬ 
larged areas form the ovaries. The primitive ovarian cells when first 
differentiated are larger than the ectodermal cells of other parts. 
Their protoplasm becomes homogeneous and of a finely granular 
character. The nuclei are less hyaline in appearance; and the 
