ANTHOMEDrS.E RATH K FA. 177 



According to Gegenbaur, 1854 (Generationswechsel Polypen und Medusen, pp. 22 28, 

 Taf. 2, fign. I -9), the egg of Rathken fasciculata develops into a solitary polyp covered with a 

 horny peritheca and provided with 4 tentacles. The segmentation stages were studied by 

 Metschnikoff, 1886. 



The oral tentacles in the young medusae are unbranched, hut in the majority of the 

 species they become torked as growth proceeds. In Rathken hlonJinn (I.izzia blonJinii 

 Forbes) they remain simple and unbranched throughout life. It appears best, however, not 

 to separate Lizzifi from the older genus Rathkea on the ground that I.izzia has simple tentacles 

 throughout its life, for all of these medusa; have simple oral tentacles when young and their 

 forked character in later life may better be considered specific rather than generic. 



Rathkea blumenbachii Brandt. 



Oceania blumenbachii, RATHKF, 1X55, Mem. Acad. Imp. Sci. St. Petersbourg, tomr 2, p. 321, laf. I, fign. 1-4. 



(?)C\tifis octopunctata, SARS, 1835, Beskriv og Jagttag, p. 28, plate 6, figs. 14*2-14^. 



Rathkia blurnenbachiana, BRANDT, 1837, Bull. Sci. Acad. St. Petersbourg, vol.i, No. 24, p. 187. Also: R. Oceania blumenbixhii, 



1838, Mem. Acad. Imp. Sci. St. Petershourg, ser. 6, tnmc 4, p. 353. 

 Rathkea blumenbachii, HAFCKEL, 1879, Syst. tier Medusen, p. 96. 

 Rathkea blumenbachi, BF.DOT, 1905, Kevin- Suisse ile Zool., tome 13, p. 144 (literature- iS;i;-5o). 



This medusa has a pyriform bell with thick, gelatinous walls. Bell-cavity about two-thirds 

 as deep as the bell-height. 8 marginal clusters, each with 3 tentacles all of equal length and as 

 long as the bell-height. 4 radial-canals. Stomach mounted on a short, conical peduncle. 

 Stomach and peduncle together are about one-halt to two-thirds as long as the depth of the 

 bell-cavity. 4 radially placed, oral tentacles, each of which forks at its end and gives rise also 

 to 4 short, side branches, i on each side of the tentacles. 8 gonads ( ?) No medusa-buds. 

 Stomach and tentacle-bulbs brownish-yellow. Sebastopol, Russia, in April. 



For further description, see synoptic table of species of Rathkea. 



Rathke's drawing is inaccurate in showing 8 radial-canals. The 4 interradial radiating 

 muscle strands were doubtless mistaken for radial-canals. I am inclined to suspect that this 

 medusa may be identical with the better-known Rathkea <it'tnpunctntu. 



Rathkea formosissima. 

 I.izzia formosissima, BROWNE, 1902, Annals and Mag. Nat. Hist., ser. 7, vol. 9, p. 278. 



Umbrella bell-shaped, $ mm. high and 2.5 mm. broad, with a slight, transverse constriction 

 level with the top of the subumbrella cavity and a solid mass of |elly above it. 5 tentacles in 

 each radial, and 3 in each interradial, cluster. Stomach small, somewhat cubical, about as long 

 as broad, and situated on a broad peduncle about as long as the stomach. Mouth with a 

 plain, simple margin, somewhat quadrangular in shape. There are 4 oral tentacles, each with 

 7 to 1 1 clusters of nematocysts consisting in a terminal cluster and 6 to 10 lateral clusters in a 

 double row. Gonads on the stomach in 4 interradial, roundish swellings or masses. The young 

 medusa; have medusa-buds upon the stomach and only } tentacles in each group. Color! ?) 

 Found at Stanley Harbor, Falkland Islands, South Atlantic coast of South America. 



Rathkea octopunctata Haeckel. 



Plate 20, fig. 1 1 . 



( >) Oceania blumenbachii, RATHKF, 1835. Mem. Acad. Imp. Sci. St. Pe'tersbourg, tome 2, p. 321, 4 figs. 

 Cyttris (?) octopunctala, SARS, 1835, Beskriv og Jagttag, p. 28, plate 6, figs. 14^-14^. 



Cytais octopunctata, SARS, 1846, Fauna Littor. Noveg., tome I, p. 10, plate 4, figs. 7-ij.--l.iNKO, 1900, Travaux Soc. Imp. 

 des Nat. de St. Pctersbourg, tome 29, p. 152, fig. 2. 



TT . . ._? . - O . ,Hf_._XT_-U'. I _ .. O . 



\taryellium octopunctatum+ Rathkea 



