SK.MA KdSTnMK.K HKSMiiNKMA. .V.l.'l 



Demonema gaudichaudii Agassiz. 



Chrysaora gamin liauilii, 1. ISMJN, iS-ij, Voyage de la Co/juille, Zooph., p. 114, Zoophytes planchc 13, fig. I. 



Couthou \ia pendulti atul Mtdora eapfn: . \,\- [/, I.., i X*.:, r>.nr . \.ii. Hi '. I . S.j '-!.4, pp. 118, !'>;. 



I)eimantma gaudichaudi, AGASSIZ, L., l86i, Coin. Nat. Hi '. I". S., vol. 4, p. ifcG. H\i< mi., 1880, Syst. dcr Mcdusen. p. 527. 



Couthouya gauji<hautli, MAAS, iqoS, Kxprd. Antarctique Francaise, Meduscs, p. 5, planclie i, 6g. I. 



Bell at least 500 or 600 mm. wide, only 5 to 7 tentacles in a single line, in each intcr- 

 rhopalar cluster. Thus when the medusa is of a greater size than I), chierchiana, if has fcwei 

 tentacles. Maas states that the color of the gastric cavity is brownish-purple, accentual < il 

 in the gonads, while the muscle-system is lighter and the gelatinous substance is bluish and 

 transparent. The medusa is found in the Antarciic region in April. Future studies will 

 probably demonstrate that /). cliifrcli'uina is onlv a variety of this medusa for they are alike 

 in all respects excepting that in Desmonema chierchiana the tentacles arise in several rows, 

 whereas in /). gaudichaudii they remain as a single row even when the medusa is much lai 

 than I), chierchiana. This difference may be due to environmental causes, or mav be of 

 the nature of a variation such as one observes in the development of tentacles in J)<ict\lrjtn,-tni 

 and Chrysaora, but until further studies have been carried out it will be safer to keep the 

 two forms specifically distinct one from the other. It is probable, however, that f). yamii- 

 i-liiiuiln is only a variety in which the tentacles remain in a single row, as in the \IUIIIL: <>t I). 

 chierchiana (see fig. 37'' L 



Further details of the structure of D. gaudichaudii may be obtained from the description 

 ot J). chierchiana which follows. 



Agassiz's Medora i-iip,-n.\i.\ is apparently a young stage of this medusa. 



Desmonema chierchiana Vanhbffen. 



Dcsmonema chierchiana, VAMHH i i .. iSSS, Bibliotheca Zoologica, Bd. i, Heft }, p. 18, taf. I, fig. 4; 1908, Deutsche SiidpiJ.ir 

 Expedition, 11)01-11)05, Bd. 10, Zonl. 2, p. 41, taf. 2, fign. 2, 3; Abbild. 5-9. BROWNE, 1908, Trans. R..yj| Sue. Edinbm 

 vol. 46, p. 244, plate i, fig. 2. 



( ? ?) Chrysaora gaudichaudii, LESSON, 1829, Voyage de la Co^uillf t Zooph., p. 114, planche 13, fig. i. 



Umbrella ^10 mm. or more wide and loo mm. high. Exumbrella smooth. The 8 pairs 

 of ocular lappets are onlv about one-third as wide as the S tentacular lappets, which are flatter 

 than a semicircle in outline. The 16 small, ocular lappets are bluntly rounded and sharply 

 set off from the 8 tentacular lappets. The subumbrella is divided into id equal sectors cor- 

 responding to the id stomach-pouches. These sectors are areas in which the circular muscles 

 are well developed and separated one from another by narrow septa. 8 of the id muscular 

 sectors are in the radii of the SI marginal sense-organs and 8 are intermediate. There aie no 

 radial-muscle strands. 



There are 8 groups of tentacles, each of which, in old medus:e. arises in several rows 

 from the subumbrella at some distance inward from the bell-margin. These tentacles are 

 developed along the outer edges ot the X interocular. circular muscle-sectors. There ai. 

 about do tentacles in each cluster, the oldest and longest being along the innermost, and the 

 shortest and youngest in the outermost rows. The lows are not U-shaped, as in Cyanea, but 

 are nearly straight. The tentacles are hollow, their entoderm being thin and the ectoderm 

 thick-walled. When voting the tentacles are somewhat flattened and the ectodermal longi- 

 tudinal muscle strands are set within infolded, Butter-like lines down the length of the ten- 

 tacle. As growth proceeds these gutters sink deeper and deeper into the ectoderm and finally 

 become inclosed tubes, sunken beneath the surface. Thus the longitudinal muscles become 

 tubular strands of fibers. A full description of the tentacles is <M\CII by Vanhoffen, i,>o8. 

 \\hen expanded the tentacles of a large medusa may be at least 20 meters Ion;;. 



The 4 mouth-curtains are well-developed and resemble those of ('.lir\><i'>r<i. The}' are 

 narrow near the mouth-opening but expand outwards and then taper gradually to a point. 

 Each mouth-curtain is i. times as Ion;: as the bell-radius and its martinis are much folded. 



J !"> D 



The 4 sac-like, protrusive gonads are folded and resemble those of (.' \',nii-/i, but are smaller. 

 There are 16 sectors ot circular muscles in the subumbrella. S in the ocular and S in ihe 

 interocular radii. These circular muscles do not extend beyond the zone of the clusters of 

 tentacles and sense-organs and are not found in the subumbrella of the lappets. There an 

 no strands of radial-muscles in the subumbrella, or in the lappets, such as are seen in (* \-iiu. 



