UHIX.OSTIIM.K KHoril.KM \. 7l 17 



of the subumbrella consists of 16 triangular areas which alternate with and art- widely sepaiatcd 

 by the 16 radial-canals. 



This medusa was described by Yanhoffen from Ilonkon, China. and later In M.I.IS 

 from the Malay Archipelago. It appears to In- identical with A" . Kishinoiue. fiom 



Japan. R. hispiditm is possibly identical with l'il,-m,i J,i\-ig,-r,i Haeckel; hut in HacckeTs 

 medusa there are only 4* marginal lappets when the disk is 90 mm. wide, whereas in A?. 

 hispidum ot the same width there are 80 marginal lappets. The granular projections upon 

 the exumhrella in Haeckel's medusa are bluntly rounded, \\heieas in A'. Inspidum ihcv aic 

 sharp and thorn-shaped. The terminal appendages of the mouth-arms appear to he some- 

 what longer in Haeckel's medusa than in K. hispiJuni. I laeckel desciihcs "I'll, m,i ,l,r, 

 from a single alcoholic specimen from 1 lon^konu, China. 



Rhopilema verrillii. 



Plate 74, figs, i, i'. 

 Nrctopitema vtrril/ii, FEWKES, 1887, American Journ. Sci., ser. 3, vol. 33, p. 119, plate 4. 



The disk is tully 350 mm. in diameter, hemispherical in contraction, but slightly Hattei 

 than a hemisphere when expanded. The gelatinous substance is thick and rigid. The cen- 

 ter ot the exumhrella is smooth, hut over the lappets there are many shallow furious and 

 the surface near the margin resembles sand-paper, being covered with numerous minm 

 vations. There are 8 marginal sense-organs, each of which contains a terminal, entodeiin.il 

 concretion-mass oi red pigment granules. There is a simple, exumbrella sensory pit without 

 furrows; 64 marginal lappets. There are 6 large, oval lappets in each octant of the margin of 

 the disk, together with 2 small, oval lappets adjacent to the sense organs. 



The arm-disk is cruciform and about half as wide as the bell, and the 4 perradial col- 

 umns are only three-fifths as wide as the heart-shaped, subgenital ostia. 8 short, tounh, 

 gelatinous, lower mouth-arms, which arise from the arm-disk, are each about 180 mm. lono 

 and Y-shaped in cross-section below. They branch sparingly and the \erv numerous mouths 

 are found upon their lower and inner sides, in furrows bordered by numerous, small, wa\in<i 

 cirri. There are about 25 to 60 blunt, translucent spindle-shaped appendages, \\luch anse 

 from the lower sides of the mouth-arms, and are besprinkled with wart-like clustets ot 

 nematocysts. '1 he largest filaments arise from the principal crotches ot the mouth-arms. 



A pair of short flapper-like, lateral scapulets arise from the outer side ot each of the 

 8 mouth-arms near its base, the mouth-openings of which are confined to their upper < 

 and connect by a main duct in each scapulet with the axial-canal of the arm to which the\ ,iu 

 attached. "I here are no appendages upon the scapulets. 4 short, gelatinous, perradial columns 

 connect the arm-disk with the subumbrella. There are 4 deep, heart-shaped clefts 01 genital 

 ostia between these 4 columns, hut the bottom of each cleft is bridged o\er by a d< 

 membrane. The 4 separate gonads develop within this membrane and the stomach is bor- 

 dered on the sides by the 4 stout, perradial columns and the 4 inter/radial memhiancs. 

 The 4 genital sacs are separated one from another; indeed the gonads are somewhat protru- 

 sive in old medusa?. 



There is a blunt wart-like papilla upon the subumbrella surface at a short distance 

 beyond the opening of each genital ostium, and this partially constricts the opening. gi\ing 

 it a heart-shaped outline. The circular muscles of the subumbrella are \ei\ poweitul, but 

 are almost interrupted in the radii of the 16 radial-canals in old medusa- although thev aie 

 entire near the margin in young animals. Thus in old medusae there are !' paniallv isolated 

 arcades of circular muscles as in Rhizrjstvtuti pulmo. Tlu-ie arc no i.ulial muscles. 



The stomach is wide and crucifoim, and corresponds m outline with the crucitoim 

 arm disk under which it lies. Its exumbrella roof is plane, but the suhumbiella floor dips 

 downward into the center of the arm-disk, and 4 open, perradial. gutter-like iun\\s extend 

 from this central depression down the center ot each perradial column to the outei edm "I 

 the stomach. 4 perradial ducts arise from the depressed center of the stomach at the 

 middle of the arm-disk, and these soon bifurcate giving 8 adradial ducts \\hnh t \tend do\\ n 

 each of the 8 mouth-arms giving offside branches to the numerous mouths. 



