290 



MEDUSAE OF THE WORLD. 



may be as numerous as tentacles, but are readily lost. Manubrium small and short, with 

 4 narrow, frilled lobes. Gonads narrow, on nearly the entire lengths of the 4 radial-canals 

 leaving both ends of each canal free. Ring-canal yellow-green, tentacle-bulbs purple, edges 

 of lips with a single row of faint purple spots. Common in surface hauls off San Diego, 

 California, from May to July. 



This species is readily distinguished by its flat, discoidal bell, three or four times as 

 broad as high. It differs from Mitrocoma anna in its color and in having fewer marginal 

 cirri. 



Mitrocoma polydiademata. 



Tiaropsis polydidemata, Romanes, 1876, Journal Linncan Soc. London, vol. 12, p. 524; Ibid., 1877, vol. 13, plate 15, fig. 3. 



Mitrocomella pohdiadema, -Haeckel, 1879, Syst. der Medusen, p. 185. 



Mitrocomella polydidema, Browne, 1895, Proc. and Trans. Liverpool Biol. Soc, vol. 9, p. 279. 



Mitrocomella fulva (young medusa), Browne, 1903, Bergens Museums Aarbog, No. 4, p. 17, plate 1, fig. 3; plate 3, figs. 1, 2. 



Mitrocomella polydiademata, Browne, 1905, Proc. Royal Soc. Edinburgh, vol. 25, p. 767. 



Bell nearly hemispherical and about 12 mm. wide. About 48 tentacles, long and slender, 

 with conical basal bulbs. 300 or more long, marginal cirri arising from bell-margin between 



tentacles, not from the sides of the exum- 

 brella; 4 to 10 of these cirri between each 

 successive pair of tentacles. Each cirrus 

 terminates in a small, oval cluster of nema- 

 tocysts. 16 marginal lithocysts, each con- 

 sisting of a large open fold of the velum 

 containing about 30 concretions. Velum 

 narrow; 4 straight, narrow radial-canals. 

 The manubrium is very small, with a quad- 

 rangular base, flat, and with 4 small folded 

 lips. The 4 gonads are linear and extend 

 over the outer 0.75 of the radial-canals. 

 The stomach, gonads, and tentacle- 

 bulbs are rich purple-red, the gonads being 

 occasionally yellowish-brown. 



The medusa is rare and occasional, 

 and has been taken in a few localities off the British and Norwegian coasts; Cromarty 

 Firth, Scotland; Port Erin, Isle of Man; Plymouth England; and Byfjord, Norway. It 

 occurs in spring and summer. Hydroid unknown. 



Mitrocoma lendenfeldi. 



Mitrocomium annce, von Lendenfeld, 1884, Proc. Linnean Soc. New South Wales, vol. 9, p. 606, plate 29, figs. 56-60. 



Bell flat, cone-shaped; 5 mm. wide and 2.5 mm. high. 8 tentacles, 4 radial, 4 interradial; 

 1.5 times as long as diameter of bell. These tentacles have globular basal bulbs, flanked on 

 either side by a cluster of short cirri which arise from the bell-margin and from the sides of the 

 basal bulbs; a black ocellus on outer side of each tentacle-bulb. 16 marginal lithocysts upon the 

 bell margin, 2 between each successive pair of tentacles. "No marginal bulges." Stomach 

 small, globular, with 4 dark interradial spots; it is connected with the bell by a narrow 

 peduncle and is only about one-third as long as depth of bell-cavity. There are 4 extended, 

 simple lips, and 4 oval gonads on the 4 radial-canals near the ring-canal. Each gonad is 

 attached to the radial-canal by a narrow neck. Gonads pale greenish-yellow. Entoderm of 

 stomach brown. Ocelli black. Port Jackson, New South Wales, Australia. Rare, found 

 from April to June. This species is certainly not identical with Haeckel's M . anna. 



Genus CAMPALECIUM Torrey, 1902. 



Campalecium, Torrey, 1902, Univ. California Publ. Zool., vol. i,p.48. — Hartlaub, 1905, Zoolog. Jahrbuchern, Suppl. 6, p. 602. 



Hydroid. — Hydrothecae arranged alternately on hydrocaulus, shallow, saucer-shaped, 

 incapable of containing the large hydranths in contraction. Margin smooth; hydranth with 

 conical proboscis and one whorl of filiform tentacles. 



Fig. 157. — Mitrocoma polydiademata, after Browne, in Bergens 

 Museums Aarbog, 1903. 



