18,1 Light: Philippine Scyphomedusan Jellyfishes 39 
this leads to a very unpleasant situation exemplified by the two 
species of Lobonema, which will be discussed later. 
The present description from living material has added many 
points not discernible in fixed material, such as the presence of 
an ocellus in the sense organ which fades out in formalin mate- 
rial, the remarkable coloration of the exumbrella, and the pres- 
ence of the long, characteristic mouth-arm clubs which break 
off when the medusa is taken from the water. 
Mayer (1915, p. 187), speaking of Cotylorhiza pacifica, says: 
It differs from Cotylorhiza tuberculata in having no radial-muscles, and 
in the circular muscles being interrupted in the 8 principal radii. The sub- 
genital ostia and arm-disk are larger and the appendages of the mouth- 
arms smaller and fewer than in C. tuberculata. Moreover, the peculiar 
window-like openings in its mouth-arm membranes at once distinguish this 
8 1es. 
hae distinctions are indeed of such a nature that if one felt so in- 
clined a new genus could be established to receive this medusa. I believe, 
however, that its relationships will be more clearly indicated by placing 
it in the genus Cotylorhiza, within which it forms a well-marked species. 
In view of the additional differences here brought out such 
as the presence of an exumbrellar sensory pit, an ocellus, a ring 
canal and the large, distinctive, mouth-arm clubs, it becomes 
necessary to erect a new genus to receive this very characteristic 
species which, while it resembles Cotylorhiza in certain points, 
differs from it very widely in many important characters. This 
resemblance I have indicated in the name Cotylorhizoides. 
IMMATURE FORM OF COTYLORHIZOIDES PACIFICUS (FIG. 4) 
A small medusa measuring in the specimens seen from 20 
to 30 millimeters in diameter is present in small numbers in 
Manila Bay at irregular intervals. In its superficial appearance 
it resembles Mastigias papua, having the same brownish color 
of the bell and a terminal club on each mouth arm predominantly 
purple in color. 
More careful examination shows it to agree in generic char- 
acters with Cotylorhizoides, and to differ from Cotylorhiza pact- 
fica only in characters which might well be due to immaturity. 
The points in which it differs are the lack of the white spots 
which characterize the adult Cotylorhiza pacifica and the ab- 
sence of the pedunculated clubs on the mouth arms. 
The number and arrangement of the marginal lappets are 
those characteristic of Cotylorhiza pacifica; that is, in each 
octant, a pointed ocular lappet, two single velar lappets, two 
double velar lappets, two single velar lappets, and a single ocular 
