212 MEDUS.E OF THE WORLD. 



Lesson first found this medusa off the west coast of Africa ( ?). Haeckel describes it from 

 the West Indies, and I have taken it upon the surface of the Gulf Stream off the Bahamas and 

 near Tortugas, Florida, from March to July. The males greatly outnumber the females. 



Distinguished from O. agariciforme Keller, from the Mediterranean, by having 32 lips 

 instead of only 7, as in O. agariciforme. 



Usually very rare, but abundant during the spring and summer of 1907, at Tortugas, 

 Florida. 



Orchistoma agariciforme Keller. 

 Orchistoma agariciforme, KELLER, 1884, Recueil Zool. Suisse, tome I, p. 418, taf. zi, fign. 1-3. 



Found by Keller at Naples, Italy. Similar to Orchistoma pileus in all respects except 

 that there are but 7 lips instead of 32, as in the Atlantic species. The color is not described 

 by Keller, who found only one mature and one young specimen. Like the Atlantic form, it is 

 very rare. 19 or more (about 32 ?) radial-canals. Keller states that the gonads are diverticula 

 from the stomach which extend outward along the radial-canals. 



Orchistoma tentaculata Mayer. 



Plate 24. fig. i. 



Orchntoma tentaculata, MAYER, 1900, Bull. Mus. Comp.Zool. at Harvard College, vol. 37, p. 8, plate 5, fig. 19. NUTTING, 1901 , 

 Bull. U. S. Fish Com. for 1899, p. 377, fig. 92. HARGITT, 1904, Bull. U. S. Bureau of Fisheries, vol. 24, p. 44, I fig. 



Youn% medusa. Bell 6 mm. in height. Sides near margin slightly flanged outward. 

 Gelatinous substance of upper part of bell very thick, so that concavity is shallow. 32 mar- 

 ginal tentacles in various stages of development, the longest being about 1.5 times as long 

 as bell-height. Tentacles with long, hollow basal bulbs. No marginal sense-organs. 16 

 functional radial tubes and 16 others in process of development. Radial tubes straight with 

 no traces of gonads upon them. Velum well developed. Manubrium flat and shallow, 8 lips. 



The entoderm of the basal bulbs of the tentacles delicate green. 



Only one immature specimen of this medusa has ever been seen; no gonads were visible. 

 It was found on the surface at Newport, Rhode Island, August 18, 1896. 



Nutting states that the tentacle-bulbs are red. They are certainly green by reflected 

 light, but probably red by transmitted light. Descriptions of color in this work are based 

 upon the appearance presented by reflected light. Professor Nutting's figure and mine are 

 drawn independently from the same specimen while yet alive. 



The differences between this medusa and 0. pileus are so considerable that it does not 

 seem possible that the one can be the young of the other. 



Genus TIMOIDES Bigelow, 1904. 



Timoides, BIGELOW, 1904, Bull. Mus. Comp. Zool. at Harvard College, vol. 39, p. 254. 



The only known species is Timoides agassizn Bigelow, of the Maldive Islands, Indian 

 Ocean. 



GENERIC CHARACTERS. 



Thaumantiad.-c with 4 radial-canals and a ring-canal which gives rise to blindly ending, 

 centripetal canals. Stomach mounted upon a peduncle. Tentacles numerous, without lateral 

 cirri. Numerous cirri upon bell-margin. There are no lithocysts. 4 gonads on the 4 radial- 

 canals. Dr. Bigelow, upon re-examining his 'specimens, tells me that the medusa has no 

 lithocysts. 



Timoides agassizii Bigelow. 

 TimoiJes agassizii, BIGELOW, 1904, Bull. Mus. Comp. Zool. at Harvard College, vol. 39, p. 254, plate 3, figs. 10, n. 



Medusa bell-shaped with rounded dome and flaring sides; 20 mm. wide, 14 mm. high, 

 with very thick gelatinous substance at apex, but thin at margin. 32 tentacles, 4 radial, 4 

 interradial, 8 adradial, and 16 intermediate. The 4 radial tentacles are at the ends of the 4 

 radial-canals. The 4 interradial and 8 adradial tentacles are at the bases of the 12 interradial 



