796 PROF. J. R. GREENE ON A RARE MEDUSA. [Dec. 16 



the tropical and subtropical regions of the Atlantic, and iu the Medi- 

 terranean ; while in latitude they extend from Nice and the Adriatic 

 (C marsupialis) to Santa Cathariua. 



According to Agassiz l , " Charybdea bitentaculata, Q. and G., is a 

 Campanella 2 ; Ch. bicolor, Q. and G., constitutes a distinct genus, 

 Quoya, Ag. ; Ch. campanella, Less., may also constitute a distinct 

 genus." — "It remains doubtful to what genus Lesson's Marsupialis 

 flagellata, from New Guinea, ought to be referred. It constitutes, 

 probably, a distinct genus, on account of its tentacles." 



Semper has given us precursory notices of some half-dozen species 

 of Charyhdeida from the Philippine shores. The full details of his 

 researches on these and other acalephs are looked forward to by mauy 

 naturalists with great interest 3 . 



1 ' Contributions, vol. iv. p. 174. 



2 To which genus Agassiz also refers Charybdea capitulum, Q. & G. MS., 

 De Bl. auct. See his explanatory note in ' Oontr.' vol. iv. p. 169. 



3 Semper found three species round the Pelew Islands. The first was more 

 than 7" high, scarcely 3" across. Wall of disk extraordinarily thick, almost 

 cartilaginous, quite colourless and transparent. The four tentacles were torn 

 off just beyond their broad cartilaginous basal portions. A wide depending 

 veil. Margin weakly lobed : just above it, in as many depressions capable of 

 being closed, were the four marginal bodies. Manubrium dependent, not lobed. 

 Central cavity of disk small. Lateral pouches very broad from their origin : 

 between two contiguous pouches the umbrellar and subumbrellar walls were in 

 contact, giving rise to tbe false appearance of a canal. Gastric tentacles in four 

 double groups about the central cavity. But one (not-sexual) example 

 (Taf. xxxix. f. 9). 



The disk of the second species was only 1 J" high, £'' across. Tentacles ex- 

 tensile to about twice the length of disk, with narrow basal lobes. Veil more 

 complicated than in last species, always elevated, and held in this position by 

 four subumbrellar septa, each springing from the mid line of a swelling, on the 

 umbrellar aspect of which is the depressed cavity, opening outwards, whence 

 the marginal body arises : septa perpendicular to subumbrella, and extending 

 across the veil, which by them is hindered from assuming a horizontal position. 

 Into each of the four broad lateral pouches freely project two sexual lamina?, 

 of which one arises on either side of tbe partition between two adjacent pouches. 

 Sexual products discharged through a single series of small openings, which 

 run close beside the attached border of each genital plate and lead into the 

 literal pouches. Manubrium short, four-lobed. Central cavity wide, with 

 four double groups of gastric tentacles (Taf. xxxix. f. 8). 



A conspicuous nerve-ring exists in this and the preceding species. It pursues 

 a zig-zag course (with eight octants), ascending slightly on either side of each 

 marginal body, then descending and reaching its lowest point near the outer 

 margin of the disk in the mid line of a tentacular lobe. 



The third species, scarcely i" high, differs in many points essentially from 

 the two others. Tentacles four, ringed with brown and yellow, destitute of 

 basal lobes. Of a beautiful yellow tint were likewise the sexual laminae and 

 four groups of gastric tentacles. No veil. Margin strongly eight-lobed, bearing 

 a shorter rudimentary tentacle between every two principal tentacles. The 

 four very broad lateral pouches interrupted in their inferior third by thickenings 

 of the substance of the disk, constituting the floors of the small cavities for the 

 four marginal bodies. Each of the eight sexual laminae much indented about 

 the middle of its free margin. Only two examples were secured ; so that some 

 structural features could not be clearly determined (Eeisebericht, 1863). 



A fourth species, fished up in May during a voyage from Manila to Komblon, 

 was very like one of the forms just noticed. Prom July to September Semper 



