188 Papers from the Department of Marine Biology. 



Light finds that Mayer is mistaken respecting the habits of this medusa and 

 that it is not a bottom form, but swims in shallow water near the surface. 



Seven specimens 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 found on March 11, 1908. This largest specimen serves as the 

 type of the species in the 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. 



Another specimen of medium size, nearly mature, was found at Cavite 

 Anchorage, Manila Bay, Luzon, on July 2, 1909. 



Light (1914) states that this is the commonest medusa in Manila Bay in 

 November and December. 



Catostylus townsendi, sp. nov. 



This species is named in honor of the author's friend Dr. Charles H. Town- 

 send, the distinguished Director of the New York Aquarium. 



Six specimens were found at Station D 5594, September 30, 1909, about 6 

 miles off Mount Putri, Borneo, in 1 1 fathoms. This medusa is closely allied 

 to Catostylus purpurus of Manila Bay, Philippine Islands, but in formalin its 

 exumbrella is milky in color and bespeckled irregularly with numerous con- 

 spicuous purple-broAvn spots. The mouth-arms are more pointed than in 

 C. purpurus. In some octants of the bell-margin the velar lappets are arranged 

 as in C. purpurus, but they are usually more numerous and more irregularly 

 arranged than in C. purpurus. 



The dimensions of the largest specimen of C. townsendi, stated in millimeters, 

 are as follows: Bell 97 wide, flatter than a hemisphere, exumbrella finely 

 granular, gelatinous substance of a horny rigidity. Shape and consistency of 

 the bell as in C. purpurus. 8 rhopalia without ocelli, in formalin, and with a 

 deep dark-colored, furrowed, exumbrella pit. 



The rhopalar lappets are small and oval, but the velar lappets are about 

 twice as wide as long. Deep clefts between the lappets extend a short distance 

 up the sides of the exumbrella. The velar lappets are very irregular in 

 arrangement, although they tend to conform to that seen in C. purpurus of 

 Manila Bay, Luzon, yet in most of the octants the subdivisions of the principal 

 lappets are more pronounced and irregular than in C. purpurus, so that there 

 are usually 7 or 8 main velar lappets with 10 to 14 marginal lobes in each octant. 



The arm-disk is similar in shape to that of C. purpurus. It is 61 mm. in 

 perradial and 45 mm. in interradial diameter. The perradial columns are 

 17 mm. and the subgenital ostia 20 mm. wide. The projections and papillae 

 of the subgenital ostia are similar to those of C. purpurus. The subgenital 

 cavity is unitary. 



The 8 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, are about 31 wide. 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 subumbrella, 

 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 4 perradial columns of 

 the arm disk, as in C. purpurus. 



16 radial-canals arise from the cruciform central stomach. The 8 rhopalar- 

 canals extend straight to the rhopalia but the 8 adradial-canals end in the 



