68 MEDUSA. I. 



separate the genera Halopsis aud Stouiobracliiiwi. It is very probable that the two genera cannot be 

 kept apart. But nothing definitely can be stated about the matter, as the two species of Siomobrachium 

 [lenticulare Brandt and tentaculatum A. Agassiz) are very deficiently described and have never been 

 found again since the original descriptions were published (Brandt 1835, p. 358. Taf. Ill, Fig. 6, 7. — 

 A. Agassiz 1865, p. 98, figs. 140—142). Neither cirri nor marginal vesicles have been observed in any 

 of the sj^ecies of Stoiiiobracliium. 



Halopsis oceLlata has never been recorded from the European waters, though it is actually not 

 uncommon in the Atlantic between the British Isles and Iceland '. 



A few of the specimens at my disposal are in the collection of the Plankton Laboratory in 

 Copenhagen. The medusae of that collection are mostly identified by Professor Damas, who has la- 

 belled the specimens of Halopsis ocellata as Stoniobrachhim jiorvegicum. I have never seen this name 

 mentioned in the literature, and Dr. Browne, on inquiry, has informed me that neither he knows that 

 name. Damas has possibly been of opinion that the specimens represented a new species; but a 

 description was never published. Owing to the war I have not been able to communicate with Professor 

 Damas concerning the matter; a letter, sent to him, has never been answered and has, probably, not 

 reached him. As mentioned above, I consider it to be beyond any doubt that this North-European 

 medusa is identical with the North-American Halopsis ocellata A. Agassiz. 



Material (see Chart IX|: 

 Iceland: 



1) — Lat. 63°43.5' N., Long. 22°22' W., .south of Reykjanses. July 8th 1904. Depth 109 m. "Thor" 

 Stat. 174 (04). — 2 specimens. 



2) — Lat. 63°i8' N., Long. 2i°3o' W., south of Eyrarbakki. July 8th 1904. — Depth 178 m. Young- 

 fi.sh trawl, 70 m wire. "Thor" stat. 176(04). — i specimen. 



3) — Lat. 62°43' N-i Long. 20°42' W., south of the Vestman Islands. July 9th 1904. Young-fish 

 trawl, 50 m wire. "Thor" stat. 179(04). — 2 specimens. 



4) — The Gulf at Heimaey, Vestman Islands. August 7th 1905. "Beskytteren", Fr. Johansen. 

 — I specimen. 



5) — South of the Myrdalsjokel. August' 17th 1903. "Michael Sars". — 3 specimens. 



6) — Under Iceland. August i6th 1903. "Michael Sars". — 5 specimens. 



7) — Lat. 64°04' N., Long. i3°48.2' W., Myri Bay. July 24th 1904. Depth 68 m. "Beskytteren", 

 Gemzoe. — 3 specimens. 



8)— Lat. 64=35' N., Long. ii°45' W., off the south-eastern coast of Iceland. August Sth 1904. 

 Depth 348 m. Young-fish trawl, 20 or 70 m wire. "Thor" stat. 241 (04). — 3 specimens. 



9) — Lat. 63°i2' N., Long. ii°45' W., between Iceland and the Faeroe Islands. August 7th 1904. 

 Young-fish trawl, 20 m wire. "Thor". — 4 specimens. 



10) — Lat. 6i°34' N., Long. i8°43' W., south of Iceland. July loth 1904. Young-fish trawl, 15 m 

 wire. "Thor" stat. 181 (04). — 2 specimens, in the collection of the Plankton Laboratory, Copenhagen. 



I Giinther (Report on the Coelenterata ... of the North AUantic. — Ann. Mag. Nat. Hist., ser. 7, vol. XI, 1903, 

 p. 426) mentions two small niedusse which "bear a considerable resemblance to the young of Halopsis ocellata as described by 

 Agassiz", but from his descri]>tion it does not seem probable that the specimens have belonged to that species. 



