L772 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
that bear upon their dorsal surfaces, at a slight distance from the bell margin, 
a row of numerous short tentacles. The 8 marginal sense organs are large and 
deeply set within niches between the marginal lappets. Sixteen narrow chy- 
miferous tubes radiate outwards from the stomach cavity. Eight of these are 
straight and unbranched, and go to the middle of the marginal lappets. The 
8 others give off side branches that anastomose. They go to the marginal 
sense organs (see Fig. 35). The mouth arms, or palps, are short and narrow, 
and do not protrude beyond the bell margin. Their free edges are lined by a 
row of numerous short slender tentacles. The 4 gonads are horseshoe-shaped, 
and the subgenital pits are wide and open. The gonads, palps, and tentacle 
bulbs of the adult Medusa are of a delicate lilac. The bell is hyaline. Young 
Meduse lack the lilac color, and are quite transparent. 
This species was common upon the surface in Suva Harbor in the early 
morning hours in December, when the water was smooth and calm. A slight 
ripple seemed to be sufficient to cause them to sink out of sight. 
RHIZOSTOM A. 
Cephea dumokuroa,! nov. sp. 
Plates 11, 12, Figs. 36-39. 
Generic Characters. Cephea, Péron and Lesueur, 1809. Discomeduse without 
tentacles, and without a central mouth opening. There are 4 sub-genital cavi- 
ties, and ventral suction cusps upon the 8 mouth arms. The mouth arms give 
off short branches that are simple and not dichotomous. There are 8 ocular 
canals, and numerous other radial canals. There are 8 marginal sense organs. 
Specific Characters. The umbrella is disk-shaped, and the walls near the 
peripheri are vertical. It is about 300 mm. in diameter. <A large dome, coy- 
ered with thick conical protuberances, arises from the centre of the aboral sur- 
face of the umbrella. There are about 20 protuberances upon the dome. About 
8 of these are large, and the remainder are much smaller. There are 8 mar 
ginal sense organs that are deeply sunken within niches upon the bell margin 
(Fig. 39). The entodermal chore of these sense organs terminates in a mass 
-of small white (calcareous?) granules. There are about 9 very short marginal 
lappets in each octant of the umbrella. There are 8 short, thick, mouth arms, — 
the ventral surfaces vf which give rise to numerous short branches covered with 
suction mouths. Rows of very small tentacles surround these suction mouths. 
There are 4 sub-genital pits (gpt., Fig. 38). A general idea of the internal 
structure of the medusa is given by Figure 38. The stomach (S) is a wide 
cavity lying within the great central dome of the umbrella. It is completely 
separated from the sub-genital porticus (s. por.) by means of the double mem- 
branous folds of the genital organs (ov.). Thirty-two tubes (see Fig. 37) radi- 
1 Dumokuro is the native Fijian name for this species. 
