MEDUSA. I. 65 



The species is very like Cosmetira pilose Ha; 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 specimens. 



The specimens are 25 30 mm wide. They 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, dis- 

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

 occupy 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 may 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 spirally coiled) 

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



' f 



Genus Halopsis A. Agassiz. 

 Halopsis ocellata A. Agassiz. 



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



Halopsis ocellata A. Agassiz 1863, Mode of Development of the marginal tentacles of ... Medusae. - 

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



A. Agassiz 1865, North American Acalephae. -- p. 99. Figs. 143 150. 

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



Fewkes 1888 a. On certain Medusae from New England. Bull. Mus. Comp. Zool. Har- 

 vard Coll. Vol. XIII, No. 7. - - p. 233. PI. Ill, fig. 3. 



Hargitt 1904. Medusae from the Woods Hole Region. - - Bull. U. S. Bureau of Fishe- 

 ries. Vol. 24. - - p. 51. 



Mayer 1910. Medusae of the World. p. 323. 



Bigelow 19143. Explorations in the Gulf of Maine July and August, 1912. - - Bull. 

 Mus. Comp. Zool. Harvard Coll. Vol. 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 margin. 



The Ingolf-Expedition. V. 8. g 



