32 THE VOYAGE OF H.M.S. CHALLENGER. 



believe, the same species in an incomplete fragment found by the Challenger expedition 

 near Mindanao, one of the Philippine Islands, at a depth of 82 fathoms. Station 201. 

 Lat. 7° 3', long. 121° 48' E. 26th October 1874. 



I name this species in honour of the meritorious Swedish naturalist, Peter Forskal, 

 who not only gave the most trustworthy description of Medusa? in the last century, and 

 was the first to describe the Medusa? of the Red Sea, but also (in 1775) made the 

 first (and hitherto best !) description and drawing of a Peganthid (Pohjxenia mollicina). 



The umbrella (PI. X. figs. 1-3) is depressed, discoid, nearly two to three times as broad 

 as high, and divided, as in all Peganthidas, by a deep horizontal coronal furrow (fig. 3, ec), 

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

 collar. The thick umbrella lens ("umbrella disk" or "gelatinous mantel") consists of 

 a planoconvex or biconvex gelatinous mass of a cartilaginous or even caoutchouc- 

 like consistency. The solidity of the gelatinous disk, connected with a high amount 

 of elasticity, attains its maximum among the Craspedota? in this family. The cause of 

 this extreme solidity are the innumerable branched, net-like, anastomosed, elastic fibres 

 which run crosswise through the gelatinous substance from the external to the internal 

 surface of the umbrella. The vertical thickness of the umbrella lens is one-third as 

 great as its greatest horizontal diameter. The exumbrella is flat, without any special 

 distinguishing character (fig. 2). The umbrella collar, which is sharply divided from the 

 umbrella lens lying above it by the deep circular constriction, consists of a circle of 

 twenty-five thick gelatinous lobes, and of the broad velum, which not only completely 

 fills the interspaces between the lobes or the pernemal incurvatures of the subumbrella, 

 and connects them like a swimming membrane, but also projects inwards a considerable 

 way about the external margin of the lobes. The limits of the umbrella collar and the 

 umbrella lens is marked by a circular line, in which the tentacles are inserted, and in 

 which the openings of the festoon canal in the periphery of the stomach lie. (Comp. 

 figs. 2, 3, 6.) 



The umbrella lobes — or more accurately " the gelatinous lobes of the umbrella collar " 

 — consist of a process of the gelatinous substance of the lens, which becomes thinner 

 towards the exterior in the direction of the margin of the lobes. Although the thick- 

 ness of the gelatinous substance in the lobes is not nearly so great as that of the central 

 lens, it is still considerable, and the lobes have great solidity. It is therefore difficult 

 to flatten out the marginal lobes, which are strongly rolled inwards both in the living 

 and the dead animal. The circle of rolled-up lobes makes the umbrella here (and still 

 more in other Peganthida?) look like the flower of the turncap lily {Lilium martagon). 

 The outline of the collar lobes is sometimes more rectangular, sometimes more pentagonal, 

 according to the state of contraction (figs. 1, 2, 6). The lateral margins, as well as the 

 point, is always strongly curved inwards ; its exumbral external surface is, therefore, 

 strongly curved both in a radial (longitudinal) and a tangential (transverse) direction. 



