REPORT ON THE DEEP-SEA MEDUSAE. 37 



Pegantha the girdle is divided into a circle of completely separate perigastral genital 

 sacs, one of each hanging freely in every lobe cavity of the umbrella collar (comp. 

 System der Medusen, 1879, p. 327, pi. xix. figs. 4-7). 



Pegantha 'pantheon, Hseckel (Pis. XL, XII.). 



Pegantha pantheon, Hreckel, 1879, System der Medusen, p. 332, No. 359. 



Umbrella crown-shaped, twice as broad as high, eighteen egg-shaped lobes, one-half 

 as long as broad. In each lobe cavity a simple genitalium in the form of a broad 

 roundish delicately-twisted leaf, eighteen tentacles twice as long as the radius of the 

 umbrella, 400 to 450 auditory clubs (23 to 25 at each lobe). Horizontal diameter, 20 

 mm. ; vertical diameter, 10 mm. 



Habitat. — The South Pacific Ocean, near Mindanao, Philippine Islands. I found the 

 extremely well preserved (male) specimen of this species, from which the figures in 

 Plates XI. and XII. are taken, in the same bottle of the Challenger collection which con- 

 tained the fragment of the preceding species. Station 201. Lat. 7° 3' N., long. 121° 48' 

 E. 26th October 1874. Depth, 82 fathoms. 



The umbrella (PI. XL fig. 1 ; PI. XII. figs. 7-9) is shaped like a diadem or crown ; 

 is nearly twice as broad (20 mm.) as high (10 mm.), and divided by a deep horizontal 

 coronal furrow into a massive upper half, the umbrella lens, and a lobed lower half, the 

 umbrella collar. The massive upper part or umbrella lens consists, as in the pre- 

 vious species, of a tolerably firm biconvex gelatinous lens, of which the horizontal 

 diameter is twice as great as the thickness (fig. 7, tig). 



The exumbrella is distinguished by branched strongly-projecting ribs, between which 

 deep radial furrows traverse the external upper surface (figs. 1-8). The ribs of the 

 umbrella lens, which increase in thickness from the centre towards the periphery, are 

 distributed so that a thicker principal rib runs in the middle of each collar lobe from 

 which several thinner secondary ribs branch out laterally. 



The umbrella collar consists of a circle of eighteen oval umbrella lobes (figs. 7, 8). 

 These "gelatinous lobes of the umbrella collar " were closely pressed together in the 

 specimen examined, and were so strongly rolled inwards, and of such a cartilaginous con- 

 sistency that they could only be opened out flat under strong pressure (fig. 8, right half). 

 They then appear of a broad oval, once and a half as long as broad. The convex 

 external surface of each lobe (fig. 2) is strongly vaulted and traversed by five projecting 

 longitudinal ribs of which the centre rib is considerably thicker than the lateral. The 

 concave inner surface of each lobe (fig. 3) encloses a roomy lobe cavity, in which hangs 

 a genital sac with folds. These eighteen lobe cavities (fig. 3, hi) form a circle of niches 

 or secondary cavities round the central umbrella cavity, and surround it like the altar- 

 niches of a circular temple (Pantheon). The central umbrella cavity itself is flat and 



