266 MEDUSAE OF THE WORLD. 



Phialidium, Leuckart, 1856, Archiv. fur Naturges., Jahrg. 1, p. 18. — Haeckel, 1879, Syst. der Medusen, p. 185. — Browne, 

 1902, Annals and Mag. Nat. Hist., ser. 7, vol. 9, p. 282. — Maas, 1904, Result. Camp. Sci. Prince de Monaco, fasc. 28, 

 p. 20; 1905, Craspedoten Medusen der Siboga Expedition, Monog. 10, p. 31; 1906, Revue Suisse de Zool., tome 14, p. 91. — 

 Beuot, 1901, Revue Suisse de Zool., tome 9, p. 485; Ibid., 1905, tome 13, p. 142. — Bigelow, H. B., 1909, Mem. Mus. 

 Comp. Zool. at Harvard College, vol. 37, p. 155. 



Campanulina (hydroid), Van Beneden, 1847, Bull. Acad. Sci. Belgique, tome 14, p. 457, plate 1, fig. 6. — Hincks, 1868, Hist. 

 British Hydroid Zoophytes, p. 186. 



Peron and Lesueur, 1809, instituted the genus Oceania, including within it medusae which 

 fall under the more modern genera Clytia, Etrene, PluahJium, Protiara, Stomotoca, Thauman- 

 tias, Pandea, and Tunis. Thus vaguely defined the name Oceania soon fell into hopeless con- 

 fusion, although more commonly applied to Tubularian medusae such as Turns than to the 

 Eucopidae. In 1862, L. Agassiz reinstated the genus Oceania, restricting it to apply to a genus 

 of the Eucopidae which had previously been segregated and defined by Leuckart, 1856, under 

 the name Phialidium. The name Phialidium thus takes precedence over Agassiz's restricted 

 Oceania and must supplant it. 



Following the lead of Agassiz, American authors have generally adopted the name 

 Oceania in his sense, whereas European writers have followed Leuckart in calling these medusae 

 Phialidium. The type species is from the Mediterranean. It is probable that this medusa 

 was previously described by Gronovius, 1760, under the name Medusa hemis phctrica and 

 should therefore be called Phialidium hemis phcencum. 



GENERIC CHARACTERS. 



Eucopidae with 16 or more tentacles and even more numerous closed, vesicular lithocysts 

 scattered more or less irregularly between the tentacles. Neither cirri nor permanently rudi- 

 mentary tentacles. The tentacle-bulbs are simple and their entodermal cores do not project 

 inward into the gelatinous substance of bell. 4 radial-canals, 4 gonads, manubrium without 

 a well-developed peduncle and with 4 lips. The hydroid is Campanulina Van Beneden. 



Phialidium is closely related to Clytia but in Clytia there are 16 tentacles alternating 

 with 16 lithocysts, whereas in Phialidium the lithocysts are somewhat irregular in arrangement 

 and always more numerous than the tentacles. Maas, 1905, institutes a subgenus, Phialucium, 

 to include medusae resembling Phialidium, but having some permanently rudimentary tentacle- 

 bulbs (no cirri) upon the bell-margin, and Torrey, 1909, institutes Phialopsis for medusae 

 with marginal cirri. 



Medusae of Phialidium are among the most abundant hydromedusae in all seas. They 

 are found, however, only near coasts and are not creatures of the open ocean, for their hydroids 

 live only in the shallow waters along the shore. Unfortunately the hydroid stocks of the various 

 species of Phialidium have been strangely overlooked, and are but little known in comparison 

 with our knowledge of their medusae. It will be impossible to be certain of specific distinctions 

 in the case of several members of the genus such as P. hemis plnvricum and P. languidum, 

 which may be identical, until a fuller knowledge of their hydroid phases is attained. 



Phialidium hemisphaericum. 



Medusa hemisphccrica, Gronovius, 1760, Acta Helvetica, tome 4, p. 35, plate 4, Basileae. 



Oceania hemispharica, Peron et Lesueur, 1809, Annal. du Museum Hist. Nat. Paris, tome 14, p. 347. 



Thaumantias hemispharica, T. thompsoni ( ?), T. sarnica, T. pileata, T. inconspicua, T . punctata, T. lineala, T. pileala, Forbes, 



1848, British Naked-eyed Medusa, pp. 47-52, plate 8, figs. 2, 3; plate 10, fig. 1; plate 11, figs. 1, 2, 4, 5. 

 Thaumantias inconspicua (hydroid), Wright, 1861, Journ. Microscop. Sci. N. S., vol. 2, pp. 202, 308. 

 Thaumantias leucostyla, Spacnolini, 1876, Catalogo Acalefi Mediterraneo, p. 27. 

 Phialidium variabile (in part), Haeckel, 1879, Syst. der Medusen, p. 186 (see also p. 128). 

 Phialidium temporarium, Browne, 1896, Proc. Zool. Soc. London, p. 489, plate 17, figs. 4-6; 1903, Bergens Museums Aarbog, 



No. 4, p. 18; 1905, Proc. Royal Soc. Edinburgh, vol. 25, p. 772. 

 Epenihesis cymbaloides (young medusa), Haeckel, 1879, Syst. der Medusen, p. 183. 

 ( >) Campanularia inconspicua, Calkins, 1899, Proc. Boston Soc. Nat. Hist., vol. 28, p. 349, plate 2, figs. 8-8<r; plate 6, fig. 8d 



(hydroid from Puget Sound). 

 Oceania favidula, Peron et Lesueur, 1809, Annal. Museum Hist. Nat. Paris, tome 14, p. 345. 

 Clytia flavidula= Oceania favidula ( ?), Peron et Lesueur= Geryonia /i/anaia, Will= Phialidium ferrugineum, Haeckel; see 



Mf.tschnikoff, 1886, Arbeit. Zool. Inst. Wien, Bd. 6, p. 241, taf . 22, fign. 9, 10, 15 (medusa from the Mediterranean). 

 Clytia flavidulum, Metschnikoff, E., 1886, Embryol. Studien an Medusen, Wien, p. 23 (egg), pp. 35, 50 (segmentation), p. 76 



(attachment), taf. 2, fign. 1-12, 21-23, 2 S~i&i tar ' 3' n 8 n - '"^' 

 Phialidium (Clytia) favidula, Maas, 1893, Ergeb. der Plankton Exped., Bd. 2, K. c, p. 61 (found off coast of Scotland). 

 ( ?) Thaumantias melanops, M'Intosh, 1889, Seventh Annual Report Fishery Board of Scotland, p. 282, plate 5, fig. 5. 



