MEDUS.E. I. 



65 



The species is ver\- like Cosmetira pilosella; it is, however considerably larger (about 30—40 mm 

 wide) and has a greater number of tentacles (about 100 against 64) and about 800 dwarf-tentacles; the 

 tentacle-bulbs are less broad. The stomach is larger, and the gonads are shorter, extending along the 

 outer one-third or half part of the 4 radial canals. The marginal vesicles seem to be somewhat more 

 flattened. 



The Zoological Museum of Copenhagen possesses 2 specimens from the following locality (see 

 Chart VIII): 



Murray Firth. September 4th — •5th 1904. "Thor". — 2 specimen.s. 



The specimens are 25 — 30 mm wide. The\- have about 100 tentacles and about 8 times as 

 many dwarf-tentacles, most of which are placed on the bell-margin itself, some being, however, di.s- 

 placed a little upwards upon the exumbrella. There are 8 large, flat marginal vesicles. The gonads 

 occup\" the distal half-part of the radial canals but do not quite reach the circular vessel. The larger 

 specimen is a male, the smaller one is a female. 



The specimens agree very well with Maas's description. Maas, however, does not mention 

 the fact that the dwarf-tentacles mav partly be situated on the exumbrella at a little distance above 

 the bell-margin. Moreover it is not appropriate to state, that the shape of the umbrella is flat; this 

 medusa has the same bent-down margin as Cosmetira pilosella. The specimens are preserved in alcohol; 

 the dark pigmentation has disappeared, and the tentacle-bulbs as well as the manubrium and the 

 gonads have now a dirty-yellow colour. 



The possession of 8 large, open marginal vesicles and the short and rigid (not spiralh- coiled) 

 dwarf-tentacles put it beyond doubt that this medusa belongs to the genus Cosmetira. 



Genus Halopsis A. Agassiz. 

 Haiopsls oceliata A. Agassiz. 



Plate IV, figs, i, 2, 3, 4, 5. Testfigs. 6, 7, 8, 9 a— r. 



Halopsis oceliata A. Agassiz 1863, IMode of Development of the marginal tentacles of . . . Medusae. — 

 Proc. Boston Soc. Nat. Hist Vol. IX. — p. 219. 



— — A. Agassiz 1865, North American Acalephse. — p. 99. Figs. 143—150. 



— — Haeckel 1879, System der Medusen. — p. 217. 



— _ Fewkes 1888 a. On certain Medusje from New England. — Bull. Mus. Comp. Zool. Har- 



vard Coll. Vol. XIII, Xo. 7. ~ p. 233. PI. Ill, fig. 3. 



— — Hargitt 1904. Medusa; from the Woods Hole Region. — Bull. U. S. Bureau of Fishe- 



ries. Vol. 24. — p. 51- 



— — Mayer 1910. Medusa; of the World. — p. 323. 



— — Bigelow 1914 a. Explorations in the Gulf of Maine July and August, 1912. — Bull. 



Mus. Comp. Zool. Harvard Coll. \'ol. 58, No. 2. — p. 102. 



Description: Umbrella is watchglass-shaped, the gelatinous substance comparatively thick, 

 particularly so in the central part of the disk, evenly diminishing in thickness towards the margm. 



The Ingolf-Expedition V. 8. 9 



