40 The Philippine Journal of Science 1921 
lappet, making ten in all if the individuals of the double lappets 
are counted. 
The sense organ appears large and shows a distinct brown 
ocellus which does not fade in formalin as does that of the 
adult. The small but deep exumbrellar pit agrees with that of 
the adult Cotylorhiza pacifica. 
The terminal mouth-arm clubs of the immature form are 
nearly as long as the mouth arms ; these clubs are purple, except 
at the somewhat swollen, three-sided distal region, where they 
are frosty white. 
That these are immature forms is shown by the absence of 
well-developed gonads, the small size, the large size of the sense 
organs and ocular lappets in proportion to the size of the velar 
lappets, and the fact that at the inner base of each mouth-arm 
pillar there is often found a portion of the original central 
mouth as yet unclosed. 
SYSTEMATIC POSITION OF ANOMALORHIZA AND COTYLORHIZOIDES 
The two new genera of Rhizostomata dichotoma here de- 
scribed but emphasize, as Mayer has already pointed out, that 
we are not dealing with a sharply defined group. He states 
(1910, p. 663) : 
There is no sharp line of demarkation between the Rhizostomata dicho- 
toma with mouth-arms V-like in cross-section and the Rhizostomata trip- 
tera wherein the arms are Y-shaped in cross-section. 
He points out that further means of differentiation are the 
strong radial and weak circular muscles and the absence of the 
ring canal in Rhizostomata dichotoma. In Cotylorhizoides, how- 
ever, there are very strong circular muscles, no visible radial 
muscles, and a ring canal. The only char- 
acters left to place it among the Rhizos- 
tomata dichotoma are the division of the 
mouth arms and the arrangement of the 
mouths upon the mouth arms. A glance at 
fig. 4, which is a very true representation 
of the appearance of an immature speci- 
men of this species, will show how striking- 
ly it simulates the appearance of the Rhizos- 
tomata triptera, particularly Mastigias 
with which it is very apt to be confused. 
(Mayer), xi. Indeed, a study of this species seems to 
show a much greater affinity to Mastigias with its club-shaped 
appendages terminating the mouth arms, its numerous anasto- 
mosing interradial canals, its large subgenital ostia, its ring 
