BAHAMA MEDUSiE. 13 



sixteen well developed, tightly coiled tentacles, and about 112 small mar- 

 ginal cirri. A dark brown entodermal ocellus is found near the base of each 

 cirrus. There are sixteen radial canals, which arise from the gastric por- 

 tion of the manubrium in four radially situated groups of four canals each. 

 The manubrium has a wide basal peduncle which fills the major portion of 

 the bell-cavity. Eight prominent recurved lips. The sixteen gonads are on 

 the proximal parts of the sixteen radial canals close to the manubrium. En- 

 toderm of manubrium dull yellow or green, and of tentacle-bulbs dull brown- 

 ish yellow. Common at Bahamas and Tortugas, Florida, in summer. 



Willia ornata, McCradt. 



Fig. 12, Plate II. 



McCkadt, J., 1857; Gymn. Charleeton Harbor, p. 47, PI. 9, Figs. 9-11. 

 Agassiz, a., 1865 ; North Amer. Aeal., p. 171. Figs. 274a-379. 



Bkooks. W. K., 1881 ; Studies Johns Hopkins University Marine Lab., Vol. II., p. 144. 

 Willia gemmifera, Fewkes, J. W., 1882 ; Bull. Mus. Comp. Zo81. at Harvard Coll., Vol. IX., 

 p. 300, Fig. 34, PI, I. 



Bell hemispherical, 5 mm. in diameter, with a small apical projection. 

 There are sixteen marginal tentacles with well developed bulbs, each of which 

 arises at the point of juncture betwem the radial vessels and the circular 

 canal. Four radial canals arise from the manubrium, and each of these gives 

 rise to three side branches, so that sixteen canals reach the circular vessel. 

 Sixteen very slender tubes arise from the circular canal and each ends blindly 

 within the gelatinous substance of the bell. Several distinct clusters of 

 nematocysts are usually found on the ex-umbrella surface immediately over 

 each of these tubes, although in some individuals there is but a single cluster 

 over each tube. The manubrium is wide and flask-shaped, and provided with 

 four prominent recurved lips. The gonads are situated at the four radial 

 corners of the manubrium. The entoderm of the manubrium is sage-green- 

 yellow, while the tentacle-bulbs are brownish. In every respect this medusa 

 resembles the Willia ornata of Charleston and Newport harbors. It seems 

 probable that Willia gemmifera is only a southern variety of this medusa 

 which produces medusae asexually through budding at the points of juncture 

 of the four radial canals with the manubrium. The only difference of spe- 

 cific value between gemmifera and ornata is that in the former there is but 

 one cluster of nematocysts over the blindly ending diverticulte of the circu- 

 lar vessel, whereas in W. ornata there may be one or several such clusters 



