194 



ERNEST WARREN. 



form layer of perisarc continuous with tlie inner laminated 

 layer of the stem (text-fig. 3, b). An umbrella-cavity (n. c.) 

 appears at an early stage with ectoderm on ectotheca {p. e.) 

 and endotheca {g. e.) Later on the umbrella-cavity becomes 

 relatively small and is mostly confined to the apical region of 

 the gonophore (text-fig. 4, a and b). Below the apically- 

 situated cavity the endotheca, consisting of the generative 

 epithelium^ is continuous with the ectotheca ; but there are 

 gradually developed four canals (PL XXXIII, fig. 4, 6-p., and 

 text-fig. 4, 6'|).) which are continuous with the umbrella- 

 cavity in the apical region, and are situated in such a manner 



Text-fig. 3. 



A. Polyp-bvid. X 100. b. Young gonophore. x 70. 



c. Thin membrane covering bud. ch^. Outer striated layer of perisarc. 

 ch'. Inner laminated layer of perisarc. g.e. Grerminal epithelium. 

 u.c. Umbrella cavity, ex. Ectoderm of Ectotheca. 



as to alternate with the endodermal radial canals (?•. c.) An 

 endodermal lamella {en. I.) is present, connecting together the 

 radial canals. 



The male and female gonophores differ in shape. The 

 male is a somewhat elongated ovoid, about 1*20 mm. in 

 length, and 0"70 mm, in breadth, and is so placed that it lies 

 almost parallel to the parent stem. The female gonophore 

 is more nearly spherical, about 1"10 mm. in length, and 

 0'99 mm. in breadth, and it tends to stand out nearly at right 

 angles to the stem (PL XXXIII, figs. 3 and 5). 



The umbrella-cavity {u. c.) of the mature female gonophore 

 has an apical opening (o. 7i.) surrounded by nematocysts (n.) ; 

 but it does not communicate with the exterior on account of 



