SCYPHOMEDUSAE COLLECTED BY STEAMER ALBATROSS. 



213 



tomosing vessels, which may join with the radial-canals, but which 

 do not connect directly with the central stomach. Among characters 

 of minor importance, the marginal zone of circular muscles in the 

 subumbrella is only partially interrupted in the eight principal radii. 

 There is an exumbrella pit with radiating furrows above each sense- 

 organ. 



CATOSTYLUS PURPURUS Mayer. 



Cato stylus purpurus Mayek, 1910, Medusae of the World, vol. 3, p. 671, fig. 

 412. — Light, 1914, Philippine Journ. of Science, vol. 9, p. 207. 



This form is closely related to Catostylus stiphropeterus, from 

 Ternate, but differs in the number and arrangement of its marginal 

 lappets and in its deep uniform purple-brown color. Light (1914) 

 describes this medusa from life, whereas Mayer had only preserved 

 material. In life the bell is higher than a hemisphere, whereas in its 

 contracted state in preservative fluids, as in our figure, it is flatter 



Fig. 15. — Catosttlus purpurus, Manila Bay, Luzon. A, Oral view., six mouth-arms 

 cut off. B, Side view, bell contracted. In life it is nearly hemispherical. 

 C, Genital ostium. D, Exumbrella view of rhopalium. 



than a hemisphere. When mature it is deep purplish brown, and the 

 sense-organs have brillant silver ocellus-like spots which are larger 

 in small than in full-grown medusae. When young the medusa may 

 be plum-colored, or even translucent white. Small cyclops-like Crus- 

 tacea were found by Light to be commensal with this medusa, the 

 crustaceans lying upon the rhopalar canals close to the sense-organs. 



Light finds that this medusa is not a bottom form, but swims in 

 shallow water near the surface. 



Seven specimens (Cat. No. 27934, U.S.N.M.) found in Manila Bay 

 on December 9, 1907, are in the collection made by the United States 

 Fisheries Bureau steamer Albatross, and a larger one (Cat. No. 27980, 

 U.S.N.M.) found on March 11, 1908. This largest specimen serves 

 as the type of the species in the United States National Museum at 

 Washington. Its dimensions in millimeters are as follows : Bell 115 

 wide, evenly rounded, 35 high ; arm-disk 75 wide where it arises from 

 the subumbrella, 52 wide at level of origin of mouth-arms; mouth- 

 arms 58 long, upper arm 7 long, lower arm 51 long and 30 wide. 



