272 MEDUSA OF THE WORLD. 



The medusa has been found by Brooks, and later by the present author among the 

 Bahama Islands, and by Bigelow off the east coast of Florida. We have often found it at the 

 Tortugas, Florida, in July. Brooks, 1888, claims to have found the hydroid stock of this 

 species. The medusa was exceedingly abundant in Nassau Harbor, New Providence Island, 

 Bahamas, late in July, 1903, and again common in the same place in April, 1907. 



Phialidium gregarium Haeckel. 



Oceania gregaria, Agassiz, L., 1862, Cont. Hist. Nat. U. S., vol. 4, p. 353.— Agassiz, A., 1865, North Amer. Acal., p. 74, fig. 103. 

 Phialidium gregarium, Haeckel, 1879, Syst. der Medusen, p. 188. — Mubbach and Sheabeb, 1903, Proc. Zool. Soc. London, 

 vol. 2, p. 179, plate 20, figs. 1, la. 



Bell nearly hemispherical, 12 mm. wide. 60 tentacles with large spherical bulbs. 1 or 2 

 lithocysts, each with I concretion, between each successive pair of tentacles. Stomach small 

 with 4 very long, curved, fringed lips. 4 radial-canals with linear gonads on their outer(distal ) 

 halves. Color, white. Victoria Harbor, Puget Sound, British Columbia, in summer. Hydroid 

 unknown. 



Phialidium discoidum Bigelow. 

 Plate 33, figs. 9-1 1. 



Oceania discoida, Mayeb, 1900, Bull. Museum Comparative Zool. at Harvard College, vol. 37, p. 51, plate 20, figs. 53-55. 

 Phialidium discoida, Bigelow, H. B., 1909, Mem. Mus. Comp. Zool. at Harvard College, vol. 37, p. 155, plates 6 and 38. 



Bell quite flat, with conically sloping sides, and 4 mm. in diameter. 16 very short 

 marginal tentacles with large basal bulbs; usually 3 lithocysts between each successive pair of 

 tentacles. Velum well-developed. There are 4 straight radial-tubes, upon the greater part of 

 the length of which the gonads are situated. In the female the eggs are very large and 

 prominent. Manubrium urn-shaped, and there are 4 recurved lips. The stomach, gonads, 

 and tentacle-bulbs are yellow or yellow-green. The entodermal supporting lamella of bell is 

 often of a delicate shade of green. Found at Tortugas, Florida, in summer. Hydroid is 

 unknown. This medusa is distinguished by its small size when mature and by its large 

 gonads, which are developed over the greater part of the lengths of the radial-canals, not 

 being restricted to their distal halves as in P. hemisphcerica or P. languida. 



Bigelow, 1909, has found this medusa in Acapulco Harbor, west coast of Mexico, and 

 also in the West Indies. His largest specimens were further developed than mine, being 

 5.5 mm. wide. One of his medusae, 3.5 mm. wide, had 46 tentacles. Usually there is 

 only a single lithocyst between every pair of tentacles, each with I to 4 concretions. 



Bigelow believes that P. pacifica Maas from Amboina is identical with P. discoidum. 



Phialidium globosum. 



Plate 34, fig. 4. 

 Oceania globosa, Mayeb, 1900, Bull. Mus. Comp. Zool. at Harvard College, vol. 37, p. 51, plate 9, figs. 19, 19a. 



Bell globular in form, 14 mm. in diameter; cavity of bell shallow, so that the gelatinous 

 substance is very thick. 32 large tentacles and 32 rudimentary ones. 64 lithocysts alternat- 

 ing with the tentacles. Each lithocyst contains 3 to 5 spherical concretions. There are 4 

 straight, narrow radial-canals. The 4 gonads are situated upon the distal parts of the 

 canals. Manubrium very short, 4 prominent lips. Color of entoderm of stomach and ten- 

 tacle-bulbs light-drab. Single specimen found at Tortugas, June 16, 1897. 



Phialidium gelatinosum. 

 Plate 34, figs. 1, 1'. 

 Oceania gelatinosa, Mayeb, 1900, Bull. Museum Comp. Zool. at Harvard College, vol. 37, p. 51, plate 10, figs. 20, 200. 



Bell 7 mm. high and 3.3 mm. in diameter. Gelatinous substance of upper part of bell 

 very thick. 16 well-developed tentacles and 16 rudimentary ones that may develop later. 32 

 lithocysts alternating with the tentacles; each lithocyst contains 3 to 5 spherical concretions. 

 Velum prominent. 4 radial-canals, in the upper or proximal part of which the gonads are de- 

 veloped. The manubrium is long and slender and there are 4 prominent lips. Color of ento- 



