RHIZOSTOM^ — CASSIOPEA. 649 



arranged. i6 long, violet-colored, radial stripes upon the subunibrella. The mouth-arms 

 branch in a hand-shaped manner, the terminal branches resembling fingers in shape. These 

 mouth-arms are 1.5 times as long as the disk-radius. There are no large club-shaped appen- 

 dages between the mouths, all being very small. The mouths are brown to violet. 



This variety is distinguished from the typical C. oruata by its color and by its finger- 

 shaped mouth-arms. It is found among the islands of the Malay Archipelago, at Saleyer, 

 and elsewhere. 



Cassiopea depressa Haeckel. 



Cassiopea depressa, Hakckel, 1S80, Syst. der Mejubcn, p. t;jz. 



Bell flat, shield-shaped, 100 to 120 mm. wide, 15 to 20 mm. high. Exumbrella smooth, 

 without aboral concavity or dome. 16 rhopalia, 144 wide, pointed, but not prominent lappets. 

 In each paramere 7 velar between 2 ocular lappets. 8 very wide, flat mouth-arms shorter 

 than the bell-radius and with 6 to 8 short, wide-spreading main-branches. Numerous very 

 small club-shaped vesicles between the mouths, hardly larger than the rhupalia, only 0.4 to 

 0.8 mm. long. No radial spots on the exumbrella. 



Found at Madagascar and at the Ouerimba Islands off Mosambique, East Africa. 

 Described in detail h\' Haeckel. 



Cassiopea depressa var. picta Vanhoffen. 



Cassiopeia picta, Vanhoffen, 1888, Bibliotheca Zoulogica, Bil. I, Heft. 3, p. 26, taf. 2, fign. I, 2. 

 Cassiopea depressa, var. pieta, Maas, 1903, Scyphomecluscn dcr Siboga Expedition, Monog. II, p. 43. 



Disk flat, 60 to 85 mm. wide. 14 ( ?) to 16 marginal sense-organs. 112 (7X16) velar 

 and 32 ocular lappets, all similar each to each, and blunt and small. The lappets are irregu- 

 larly developed in the two specimens described by Vanhoffen, and while there are usually 

 5 velar lappets between each successive pair of ocular lappets, in some parameres there are 

 o, 3, 8, or even 10 velar lappets. Arm-disk octagonal with 8 equal sides and half as wide as 

 bell-diameter. The free, projecting parts of the 8 mouth-arms are somewhat shorter than 

 the radius of the disk and project about one-third of their length beyond the bell-margin. 

 These mouth-arms are pinnately branched with short branches as in C. xanwchana, and have 

 no appendages excepting small lancet-shaped ones, as in C. ndrosta and C. depressa. The 

 musculature is similar to that of 6'. oinata. The 32 radial-canals give off anastomosing side 

 branches which place them all in connection one with another. There are no distinctly 

 differentiated ring-canals. 



Ground color of disk translucent opal. There are 16 large white spots over the 16 marginal 

 sense-organs, and in the large medusa these are fused into a ring of varying width, being 

 widest in the radii of the sense-organs and narrowest in intermediate positions. Peripheral 

 to this white ring are 144 white, linear-oval streaks, one over each lappet; those over the 32 

 ocular lappets smallest, those over the interocular lappets the longest. The 32 small spots 

 over the ocular lappets are fused with the 16 large, white, radial spots. 16 white rays in the 

 subumbrella appear as large egg-shaped spots, their blunt ends inwards. They are in the 

 radii of the sense-organs and extend from the outer edges of the central stomach and gonads 

 outwards with their radial edges almost touching. 



This species was described by Vanhoffen from two specimens found near Beibul in the 

 Red Sea, in December, 1884. It differs from other species of Cassiopea in the large number 

 of its marginal lappets and its very wide arm-disk. There is no raised central sucker on the 

 exumbrella and no large club-shaped vesicles on the mouth-arms, such as are seen in C. 

 polypoides. 



Cassiopea mertensii Brandt. 



Cassiopea mertensii, Brandt, 1838, Mem. Acad. Sci. St. Petersbourg., Sci. Nat., ser. 6, tome 4, p. 396, taf. 20-23. — Hafckel, 



1880, Syst. der Medusen, p. 572. 

 Cassiopeja mertensii, Maas, 1903, Scyphomedusen der Sihoga Exped., Monog. it, p. 40. 



Bell evenly rounded without an aboral concavity, 100 to 120 mm. wide, 30 to 40 mm. 

 high. 16 rhopalia. 128 small, tongue-shaped, prominently projecting lappets. In each 

 paramere 6 velar between 2 ocular lappets. 8 cylindrical mouth-arms 1.5 times as long a 



