232 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



of the convexity of the bell. The dome may be sky blue, rose- 

 colored, or amber colored and the bell blue with reddish spots and 

 markings. Mouth-arms fused forming an eight-sided prism, flaring 

 outward below. Gelatinous substance tough Cephea. 



1. Dome low, warts small Cephea octostyla. 



2. Dome high, warts conspicuous Cephea cephea. 



Bell amber colored, about 9 inches wide, with a smooth central 

 dome without wartlike projections. Clusters of grapelike append- 

 ages on the eight leaflike mouth arms. Windowlike openings in 

 the membranes of the mouth arms. Marginal lappets of the bell 

 short and oval C otylorhiza pacifica. 



Bell smooth, hemispherical, about 8 inches wide when full grown. 

 Deep uniform, purple-brown. The commonest medusa in brackish 

 water canals in shallow water along shore in Manila Bay in No- 

 vember and December Catostylus purpurus. 



Similar to the above but with irregular purple brown spots over 

 the convex side of the bell. No filaments on the mouth arms. 



Catostylus townsendi. 



Similar to Catostylus townsendi but with numerous long filaments 

 on the mouth arms. The longest ones being near the outer ends 

 of the mouth arms Acromitus maculosus. 1 



Bell high, domelike, 4J to possibly 12 or more inches wide, slightly 

 granular on the convex surface. Yellowish-white or cobalt blue. 

 Eight tapering mouth arms without filaments or other appendages. 

 Common in the mouth of Brisbane Eiver, Queensland, Australia, but 

 widely distributed over this general region Catostylus mosaicus. 



Bell about 3£ inches wide, smooth, evenly rounded, flatter than 

 a hemisphere, milky-yellow, with smooth convex surface. Slender 

 tapering filaments in the eight mouth arms. No prominent spots in 

 the convex surface of the bell Lychnorhiza, 



1. A single long filament at the pointed end of each mouth arm. All other 



filaments very short Lychnorhiza bornensis. 



2. With numerous long filaments on the mouth arms Lychnorhiza bartschi. 



Bell smooth, about 2£ to 3^ inches wide. With eight mouth arms, 

 each tapering to end in a long naked more or less club-shaped fila- 

 ment. This small medusa pulsates and swims rapidly, is usually 

 greenish or reddish brown, and is common in harbors in the East 

 Indies. 



1. Bell blue, greenish, olive, or brown with solid white, brown or yellowish, 



spots. The eight terminal clubs on the mouth arms each as long as the 

 diameter of the bell Mastigias papim. 



2. Bell reddish brown, with ringlike spots of white and brown. Eight terminal 



clubs only about half as long as the diameter of the bell— Mastigias ocellata. 



i See S. F. Light, 1914, Philippine Journal of Science, vol. 9, section D, p. 212, fig. 4. 



