190 Papers from the Department of Marine Biology. 



Catostylus mosaicus (Quoy and Gaimard). 



Cephea mosaica, QUOY ET GAIMARD, 1824, Voyage de VUranie, Zoologie, p. 569, planche 85, fig. 3. 

 Catostylus mosaicus, AGASSIZ, 1862, Cont. Nat. Hist. U. S., vol. 4, p. 152. MAYER, 1910, Medusae 

 of the World, vol. 3, p. 666. 



A single immature medusa, which may possibly be the young of C. mosaicus, 

 was taken by the Albatross in a seine off the beach near the mouth of Malam- 

 paya River, Palawan Island, Philippine Islands, on December 26, 1908. It 

 differs from C. mosaicus in having only 10 marginal lappets in each octant 

 instead of about 16, as in C. mosaicus. Moreover, in C. mosaicus the lappets 

 are all long, pointed, and similar in size and shape each to each, whereas in 

 the Philippine medusa there are 8 long, pointed velar and 2 much shorter, 

 oval, ocular lappets in each octant. The Philippine medusa is, however, 

 quite small, being only 86 mm. in diameter, whereas C. mosaicus becomes fully 

 350 mm. wide. These differences may therefore be due to immaturity. In 

 the Philippine medusa the bell is 86 mm. wide, mouth-arms 63 mm. long, the 

 upper arms being 11 mm. and the lower 52 mm. The interradial subgenital 

 ostia are 18 mm. wide with a large oval or nearly spherical papilla on the sub- 

 umbrella. The perradial columns of the arm-disk are only 12 mm. wide, thus 

 the ostia are 1.5 times as wide as the columns. The perradial diameter of the 

 arm-disk is 52 mm. and its interradial diameter 44 mm. The powerful ring- 

 muscles of the subumbrella are only partially interrupted in the 8 chief radii. 

 The exumbrella is coarsely granular and besprinkled thickly with numerous 

 minute cinnamon-brown flecks. Other parts of the medusa are pale milky 

 pink. The gelatinous substance is tough and rigid. 



If this be not C. mosaicus it is certainly very closely related to this well- 

 known Australian medusa. C. mosaicus is abundant in bays and estuaries 

 along the Australian coast from Melbourne to the mouth of the Brisbane River 

 in Queensland. 



In Sydney Harbor all specimens of this medusa are dull creamy brown or 

 yellowish in color, but in Moreton Bay, Queensland, most of them are cobalt 

 blue. It is interesting to see that H. B. Bigelow (1914, University of Cali- 

 fornia Publications in Zoology, vol. 13, p. 239) finds that Stomolophus rneleagris 

 in San Diego Bay, California, is prussian blue instead of being dull yellow, as 

 in the Atlaritic. 



Catostylus mosaicus appears to breed throughout the year in Moreton Bay, 

 Queensland, but in the temperate regions of Australia it is said to become 

 mature only in summer and autumn. 



Genus LYCHNORHIZA Haeckel, 1880. 



Lychnorhiza-\-(.'ramborhiza, HAECKEL, 1880, Syst. der Medusen, pp. 587, 633. 



GENERIC CHARACTERS. 



Rhizostomata triptera with filaments, but without clubs, upon the 3-winged 

 mouth-arms. No axial terminal club at end of each arm, and no club-shaped 

 appendages between the mouths. The stomach gives rise to 16 radial-canals: 

 8 rhopalar and 8 adradial. The rhopalar-canals extend to the bell-margin, 

 but the adradial ones end in the ring-canal. Blindly ending, centripetal 

 vessels arise from the inner side of the ring-canal and may anastomose to some 

 extent. On its outer side the ring-canal gives off a network of anastomosing 

 vessels which extend into the lappets. 



