SCYPHOMEDUSAE COLLECTED BY STEAMER " ALBATROSS.' ' 215 



columns are 17 mm. and the subgenital ostia 20 mm. wide. The pro- 

 jections and papillae of the subgenital ostia are similar to those of 

 C. purpurus. The subgenital cavity is unitary. 



The eight mouth-arms are each about 64 mm. long, the upper, 

 naked outer part of each arm being 14 mm. and the 3-winged lower 

 part 50 mm. long. The arms are widest at the proximal parts of the 

 3-winged expansions which, when spread out, have a span of about 

 31 mm. They taper to pointed distal ends and have no appendages 

 among the mouth-frills. 



There is a powerful unbroken zone of circular muscles in the sub- 

 umbrella, 27 mm. wide, from the outer edge of the arm-disk to the 

 bell margin. There are also radial muscle fibers on the abaxial sides 

 of the four perradial columns of the arm disk, as in G. purpurus. 



Sixteen radial canals arise from the cruciform central stomach. 

 The eight rhopalar canals extend straight to the rhopalia, but the 

 eight adradial canals end in the ring canal, which is beneath an 

 annular furrow or bend in the subumbrella 13 mm. inward from the 

 bell margin. On its inner side the ring canal gives rise to from 4 

 to 7, usually 5, centripetal canals betwen each successive pair of 

 radial canals. These centripetal vessels anastomose with one an- 

 other and with the 16 radial canals, and end blindly before reaching 

 the stomach margin. On its outer side the ring canal gives off a 

 network of vessels which ramify through the lappets. In formalin 

 the medusa is opaque milky white with irregularly clustered brown 

 spots over the exumbrella. 



This medusa is closely related to Acromitus maculosus Light, 1 but 

 it has no filaments upon its mouth arms. It is possible, however, 

 that these were lost, but this seems improbable among six well- 

 preserved specimens. 



Moreover, in Catostylus townsendi the centripetal vessels anasto- 

 mose with the 16 radial canals, whereas in Acromitus, according to 

 Light, they join only with the eight rhopalar canals. It seems prob- 

 able, therefore, that Catostylus townsendi is a distinct species, sepa- 

 rate from Acromitus maculosus Light, and that Acromitus is a genus 

 derived by mutation from Catostylus. 



CATOSTYLUS MOSAICUS (Quoy and Gaimard). 



Cephea mosaica Quoy and Gaimard, 1824, Voyage de VUranie, Zoologie. 



p. 569, pi. 85, fig. 3. 

 Catostylus mosaicus Agassiz, 1862, Contr. Nat. Hist. U. S., vol. 4, p, 152. — 



Mayee, 1910, Medusae of the World, vol. 3, p. 666. 



A single immature medusa (Cat. No. 28720, U.S.N.M.) which may 

 possibly be the young of C. mosaicus, was taken by the Albatross 

 in a seine off the beach near the mouth of Malampaya Eiver, Pala- 

 wan Island, Philippine Islands, on December 26, 1908. It differs 



1 1914, Philippine Journal of Science, vol. 9, No. 3, sec. D, p. 212, figs. 4-6. 



