Noi 437.) WORTH AMERICAN INVERTEBRATES. 341 
palia 8. Manubrium cruciform, simple, devoid of arms cr appendages. 
Gonads 4, horseshoe-shaped, beneath which on the subumbral wall are four 
open sub-genital pits. Stomach large and with 16 gastric pouches, eight of 
which extend to the ocular lobes and eight to the tentacular lobes. 
Color. Disk translucent, slightly biuish; clusters of nematocysts dull 
yellowish-brown ; tentacles slightly greenish. 
Aurelia flavidula Per. & Les. Fig. 5. 
TURD 
hi Unt 
Fic. 5. Aurelia flavidula Per. & Les. 
Umbrella flat and disk-like, somewhat arched above; margin normally 
eight-lobed and with eight rhopalia located in the marginal sinuses. Many 
variations from the normal octamerous form are found in some collections 
reaching as high as 25%. 
Marginal tentacles numerous, short, forming a delicate fringe about the 
entire margin except at the rhopalial sinuses. Radial canals 16, of three 
sorts, per- inter- and adradial; the first two series branching and anastomos- 
ing freely, the last usually straight and simple from its origin to its junction 
with the marginal canal. 
Manubrium cruciform in cross section, and with four long oral arms which 
are more or less fimbriated and the margins bearing numerous batteries of 
nematocysts. Gonads crescentic in form, borne upon the floor of the four 
gastric pouches. 
Color —Aurelia is among the duller colored of the Scyphozoa, the bell 
being quite transparent, but with a bluish opalescence. The gonads present 
a pale pinkish hue, though the ova are almost clear white as examined singly. 
Distribution —Aurelia is one of the commonest of the Atlantic coast 
medusz and ranges from the coast of Maine to Florida. It is most abun- 
dant during the early summer or spring along most of the New England 
coast, though fairly abundant northward till late in summer. Its breeding 
habits seem to be somewhat continuous during most of the summer. The 
scyphistoma stage is a somewhat extended one, probably lasting over the 
entire winter season. Kept for weeks in aquaria they showed no signs of 
metamorphism. I have taken them in all stages of strobilization during 
