194 



MEDUSAE OF THE WORLD. 



ican If ' ills i a discovered by Professor Brooks, in being 6-rayed at its center, whereas the 

 center of the stomach of the American medusa is only 3-rayed. 



The stomach and gonads are yellow to reddish-yellow and the tentacle-bulbs are dark 

 yellowish-brown or purple-brown. This medusa is found off the coasts of Great Britain and 

 Ireland. It is abundant at Valencia Island off the southern coast of Ireland. 

 A summary of its stages in growth may be presented thus: 



The hydroid is " Lar sakellarum" 

 of Gosse and Hincks. It grows upon 

 the tube of Sabella. The polypites 

 arise at intervals from a creeping 

 hydrorhiza. The fusiform feeding 

 polypites are larger than the repro- 

 ductive ones and have each 2 ten- 

 tacles which both arise from one side 

 of the body. The reproductive poly- 

 pites have no tentacles and their free 

 upper ends are somewhat globular 

 and devoid of a mouth, although they 

 are armed with many nematocysts. 

 The medusa-buds arise in clusters of 

 3 to 4 on the upper sides of the body 

 of the polypite. When set free the bell is somewhat higher than a hemisphere and the 

 medusa has 6 radial-canals and 6 tentacles alternating with 6 clusters of nematocysts upon 

 the exumbrella. The stomach is 6-lobed and has 6 lips. 



Haeckel, 1879, p. 158, describes a " ff'illia furcata" from St. Nazaire, Atlantic coast of 

 France. This may be identical with W. stcllata, but it is said to have the gonads isolated upon 

 the radial-canals. The lower edge of the stomach is said to be folded or crinkled and without 

 true lips. In other respects the medusa is evidently identical with W. stellata. I suspect this 

 of being merely a specimen of l . stcllata in which the central part of the stomach has been lost 

 through accident and is in process of regeneration. 



Willsia (?) varians. 



Probosciilarlvla varians, BROWNE, 1902, Fauna ami Geography Maldive ami Laccadive Archipelagoes, vol. 2, p. 728, plate 54, 

 figs, i, 2. 



Browne describes this medusa from a single specimen with an irregular, 6-lobed stomach. 



The medusa was 3 mm. wide, 2 mm. high. 6 main radial-canals, each with I to 3 lateral 

 branches. 17 tentacles, one at the end of each terminal branch of the radial-canals. No 

 ring-canal. Clusters of nematocysts on the exumbrella. Stomach very irregular with 5 ( ?) 

 lips. No gonads, but with 2 medusa-buds upon 2 of the radial-canals near the stomach. 

 Tentacle-bulbs dark brown. Maldive Islands, Indian Ocean. This may he an abnormal 

 specimen of Probosctdactyla nrnata var. stolonifera. 



Willsia mutabilis Browne. 



li'illiti mutabilisj BROWNE, 1902, Annals and Mag. Nat. Hist., ser. 7, vol. 9, p. 280; 1904, Fauna antl Geog. Maldive and Lac- 

 cadive Archipelagoes, vol. 2, p. 729. 



Bell slightly conical, 6 mm. high and 6 mm. wide. Margin of bell slightly inverted and 

 summit broad and round. There are 24 or more tentacles. 6 or 8 radial-canals arise from 

 the stomach and each gives rise to 3 or more branches. The stomach is small, with 6 or 8 

 lobes, and the margin of the mouth is complexly folded. The gonads surround the stomach 

 and its lobes. This species is very variable. Found by Vallentine at Stanley Harbor, Falk- 

 land Islands and briefly described by Browne. Color ( ?) 



Willsia brooksii, sp. nov. 



Beautiful drawings of a young stage and also of the adult condition of this medusa 

 were made by the late Prof. William K. Brooks, while he was at Beaufort, North Carolina, 

 and were found among his unpublished figures, after his death. They were kindly pre- 



