LKPTOMEDUS.E — PHIALIDIUM. 



269 



Phialidium languidum Haeckel. 

 Plate 33, figs. 4 to 8; plate 34, fig. 5. 



Oceania languida, A. Agassiz in L. Agassiz's, 1862, Cont. Nat. Hist. U. S., vol. 4, p. 353— Agassiz, A., 1865, North Amer. Acal., 



p. 70, figs. 94-102. 

 (?) Campanularia syringa, Stimpson, 1853, Marine Invertebrata of Grand Manan, p. 8. 

 Philalidium languidum, Haeckel, 1879, Syst. der Medusen, p. 188. 

 Oceania languida, Fevvkes, 1884, American Naturalist, vol. 18, p. 196, fig. 3 (abnormality).— Hargitt, 1904, Bull. U. S. Bureau 



of Fisheries, vol. 24, p. 50, plate 5, fig. 2. 

 Oceania magnifica (southern variety), Mayer, 1900, Bull. Mus.Comp. Zool. at Harvard College, vol. 37, p. 50, plate 9, figs. 18, 



i8a(this is possibly identical with P. favidula, Peron et Lesueur, of the Mediterranean). 

 (?) Phialidium languidum, Murbach and Shearer, 1903, Proc. Zool. Soc. London, vol. 2, p. 179 (Puget Sound, British Columbia). 

 ( ?) Campanularia inconspicua, Calkins, 1899, Proc. Boston Soc. Nat. Hist., vol. 28, p. 349, plate 2, figs. 8 to 8c; plate 6, fig. id 



(hydroid from Puget Sound). 



Adult medusa (plate 33, fig. 6). — Bell somewhat flatter than a hemisphere and about 

 15 to 20 mm. in diameter. Bell-walls exceedingly flexible, gelatinous substance of only moder- 

 ate thickness. There is a large number of short, slender tentacles , full-grown individuals 

 usually with about 32 or more. There are usually about 2 lithocysts between each successive 

 pair of tentacles. Each lithocyst contains a single spherical concretion. Concretions ecto- 

 dermal and inclosed by cells of velum on bell-margin. Velum well developed. 4 straight, 

 narrow radial-canals and a slender circular vessel. Manubrium small and tubular, without a 

 peduncle, and provided with 4 slightly recurved lips. The 4 gonads are linear and developed 

 upon the outer halves of the 4 radial-canals. They begin at about the middle point of each 

 canal and do not quite extend to the circular vessel. 



Figs. 145 and 146. — Phialidium huskianum, from life, by the author. 



145. Zoological Station, Naples, December, 1907. 



146. Mousehole, Cornwall, England, October 27, 1907. 



The entoderm of the manubrium, gonads, and tentacle-bulbs is usually creamy-yellow or 

 milky in color, all other parts of the medusa being transparent; the colors are, however, 

 somewhat variable, the entoderm being sometimes green or pink. In a similarly formed 

 medusa at Tortugas, Florida, the entoderm of the stomach and tentacle-bulbs, is intense green 

 and the ectoderm purple. 



This medusa is remarkable for the extreme tenuity of the gelatinous substance of the bell, 

 which becomes distorted by the contractions of the animal so as to assume all sorts of irregular, 

 collapsed shapes. These contracted states are, however, rarely seen in medusae freshly taken 

 from the sea and are mainly due to the unfavorable influence of confinement in aquaria. 



The hydroid stock of this medusa is Campanulina languida, briefly mentioned in a note 

 by L. Agassiz, 1862 (Cont. Nat. Hist. U.S., vol. 4, p. 354), as the American species of Wrightia. 

 Unfortunately no figures of it have ever been published. 



In the youngest medusa; observed, plate 33, fig. 4, the bell is dome-shaped and consider- 

 ably higher than it is broad. There are 2 long tentacles and 2 rudimentary ones at the bases 

 of the 4 radial tubes. There are 8 primitive lithocysts situated close by sides of bases of the 

 4 primary tentacles, each tentacle-bulb being flanked by a pair of lithocysts. No gonads are to 

 be seen in the young medusa. As development proceeds the tentacles increase greatly in num- 

 ber and the lithocysts keep pace with them and remain about twice as numerous as the ten- 



