SCYPHOMEDUSAE COLLECTED BY STEAMER ALBATROSS. 



211 



Genus COTYLORHIZA L. Agassiz, 1862. 



Cotylorhiza Agassiz, L., 1862, Contr. Nat. Hist. U. S., vol. 4, p. 152. — Mayeb, 

 1910, Medusae of the World, vol. 3, p. 658. 



Generic Characters. — Rhizostomata dichotoma with eight simple, 

 bifurcated mouth-arms, the ends of which branch pinnately. The 

 four subgenital ostia are simple and funnel-shaped, and there is a 

 single subgenital porticus. The appendages upon the mouth-arms 

 are mounted upon pedunculated filaments. There are eight marginal 

 sense-organs and numerous radial-canals which anastomose laterally 

 without any definite ring-canal in the adult. The sense-clubs have no 

 ocelli and no exumbrella sensory pit. There is a unitary peripheral 

 zone of circular muscles and an inner zone of radial-muscles in the 

 subumbrella. The exumbrella 

 is smooth and without an 

 aboral " sucker-like " depres- 

 sion, but with a prominent cen- 

 tral dome without wart-shaped 

 elevations upon it. 



COTYLORHIZA PACIFICA Mayer. 



Cotylorhiza pacifica Mayek, 

 1915, Publication No. 212. 

 Carnegie Institution of Wash- 

 ington, p. 185. 



A single specimen of this in- 

 teresting medusa was obtained 

 at the launch landing in Manila 

 Bay, Luzon, Philippine Islands, 

 on January 24, 1908 (Cat. No. 

 28729, U.S.N.M. type). Un- 

 fortunately it was cut into several pieces before being preserved, 

 and this renders an attempt to study it unsatisfactory in many re- 

 spects. The bell appears to have been about 200 mm. wide, ex- 

 umbrella finely granular, with a central dome as in the Mediter- 

 ranean Cotylorhiza tuberculata. 



There are 8 rhopalia without ocelli (in formalin), and without ex- 

 umbrella pits, being similar in essential respects to those of Cotylor- 

 hiza, tuoerculata. The rhopalar lappets are short and pointed. 

 There are about eight irregularly spaced, bluntly pointed, large velar 

 lappets in each octant, and deep furrows between them extend radi- 

 ally inward over the exumbrella, as in C. tuberculata. The velar 

 lappets vary in length, but the largest are about twice as long and 

 twice as wide as the ocular lappets. 



The circular muscles occupy the entire zone of the subumbrella 

 beyond the arm-disk. They are broken in the eight principal radii, 

 and unlike C. tuberculata there are no radial muscles. 



Fig. 14. — Cotylorhiza pacifica from Manila 

 Bay, Luzon. A, An octant of the bell 



MARGIN. B, ABAXIAL VIEW OF ONE OF THE 

 MOUTH-ARMS. 



