194 Papers from the Department of Marine Biology. 



Mastigias ocellata (Modeer). 



Medusa ocellala, MODEER, 1791, Nova. Acta. Phys. Med., N. C., tome 8, Append., p. 27. 

 Cephea ocellata, PERON ET LESUEUR, 1809, Annal. du Mus. Hist. Nat. Paris, tome 14, p. 361. 

 Mastigias ocellata, HAECKEL, 1880, Syst. der Medusen, p. 623. MAYER, 1910, Medusae of the 

 World, vol. 3, p. 680. 



The Albatross found small medusae of this variety in March and April, and 

 a mature one in January in the Philippines, in 1908. It is distributed over 

 the eastern parts of the Indian Ocean and in the China Sea. 



Genus PHYLLORHIZA L. Agassiz, 1862. 



Phyllorhiza, AGASSIZ, L., 1862, Cont. Nat. Hist. U. S., vol. 4, p. 158. 



GENERIC CHARACTERS. 



Similar to the closely allied Lychnorhiza, but the centripetal vessels which 

 arise from the inner side of the ring-canal join with the central stomach, as in 

 Mastigias, instead of ending blindly as in Lychnorhiza. The canal-system 

 resembles that of Mastigias, but the mouth-arms have no terminal clubs. 



Phyllorhiza luzoni, sp. nov. 



Two specimens of this medusa were captured at a depth of 150 feet in 

 Varadero Bay, Southern Luzon, Philippine Islands, on July 23, 1908. Unfor- 

 tunately both became somewhat macerated in the preservative fluid. 



The bell of the larger and more perfect specimen is 60 mm. wide, flat, and 

 with finely granular exumbrella. 8 rhopalia without ocelli in formalin and 

 without exumbrella pits. 16 sickle-shaped rhopalar lappets, and (9X8) 72 

 rounded velar lappets which are somewhat wider but not longer than the 

 rhopalar lappets, so that the general contour of the bell-margin is circular, 

 without deep niches in the rhopalar radii. 



The arm-disk is cruciform, 32 mm. in perradial and 20 mm. in interradial 

 diameter. The subgenital ostia are 14 mm. and the perradial columns 8 mm. 

 wide, and the subgenital porticus is wide and unitary. 



The 8 mouth-arms are slender and strongly compressed laterally, their lower 

 parts being 3-winged with deeply incised lateral membranes. The naked 

 outer part of each upper arm is 13 mm. and the 3-winged lower part only 11 

 mm. long. Any appendages which may have existed among the mouth-frills 

 have disappeared in the preservative fluid owing to the maceration of the 

 specimens. 



The muscular system of the subumbrella consists of a broad, uninterrupted 

 zone of weakly developed circular muscles. In other hitherto known species 

 of Phyllorhiza the muscles are interrupted in the 8 principal radii. 



The central stomach is cruciform, 32 mm. in perradial and 16 mm. in 

 interradial diameter. 8 radial-canals arise from the stomach and extend 

 straight to the 8 rhopalia and these main canals are connected one with 

 another by a ring-canal which is 6 mm. inward from the margin of the bell. 

 In each octant 6 to 9 radiating vessels arise from the cruciform stomach anas- 

 tomosing in an irregular network with one another and with the 8 main canals. 

 On its outer side the ring-canal gives rise to a fine-meshed network of vessels 

 which ramify through the lappets. 



A color note states that the medusa was light green with grayish white spots. 



