48 



HYDROIDA 



with at Iceland. This specimen which was found on the north side of the island, was originally 

 recorded by Winther (1880), and has afterwards been revised by S:Emundsson (1902). It is a pecu- 

 liarity of the specimen that it is seated on the operculum of a Ba/aii/ix Ilainiiicri^ and not on the 

 house of the Bernhardus crab. The species has been recorded once in the Arctic water-layers near Jan 

 Mayen (v. Lorenz 1886). In a previous work (1909) I gave utterance to the supposition that the 

 variety recorded by Levin sen (1892) had probably to be referred to the high-arctic sjijccies Hydrac- 

 tinia iiwnocarpa A 11 in an. An examination of the specimens mentioned, however, shows that this suppo- 

 sition is wrong. The specimens are unquestionable Hydracti)iia ccliinata with skeleton strongly deve- 

 loped. One of the specimens is distinguished by being attached to the shell of a living Bitcciiiuin 

 hydrophaniini. The species, thus, proves able to occur now and tlien under wholly high-arctic condition;;. 



Hydractinla carica Bcrgh. 

 1887 Hydractinia carica^ Bergh, Goijlepolyper fra Karahavet, p. 3, Taf. 28, Fig. i. 

 1899 — viinuta^ Bonnevie, Norske Nordhavs-Expedition, p. 48, Tab. I, Fig. 3. 



The reptant stolons are covered by a chitinous layer of coenosarc, without small prides, but 

 bearing here and there vigorous spines, singly placed and up to 0.5 mm. high, conical with rounded 

 apex. The polyps attain a length of 2 mm., and have 10 — 14 rather vigorous tentacles placed in a 

 single whorl below the oral portion. Spiralzooids are not traceable. 



The gonophores are cryptomedusoid, placed, to a number of 3 — 6, round polyps almost wholly 

 atrophied, forming, if anything, only a short stalk, or showing rudiments of tentacles slightly indicated. 



Material: 



The Kara Sea: Petuchoffskoi Schar depth 7 fath. (the original specimen described by Bergh 1887). 



An examination of the original specimen, determined by Bergh, shows with full certainty 

 that it is the same species that has afterwards been described by Bonnevie (1899) by the name of 

 Hydractinia mitmta. The diagnoses, however, when compared, will show some points of difference. 

 Bonnevie does not mention the .skeleton-formations at all while on the other hand, the statements 

 of Bergh convey the impression of a greater resemblance io Irlydractinia rcIiiiKtta 'Cn^w it really bears. 

 Hydractinia carica lacks the small prickles found in the species last mentioned, and more vigorous spines 

 also occur rather scarcely; the latter (Tab. I, Fig. 11) are smooth and more conically tapering than those 

 of Hydractinia Sarsi. The main difference, however, between the diagno.sis of Bonnevie and that 

 of Bergh is implied in the mention of the blastostyles. Bergh states in his diagno.sis "Sporosacs 

 borne on very short, rudimentary hydrants, without or with very few (1—4) tentacles", while in the 

 diagnosis of Bonnevie we find "Fixed gonojjhores without radial canals, from 3 to 5 in circle round 

 the inconspicuous blastostyles", and in her short comment Bonnevie further .states that the species 

 is distinguished for "the complete atrophy of the gonophore-bearing hydranths". The specimens deter- 

 mined by Bergh show a great varying as to the development of the fertile polyp; it may, as he tells 

 us, have 1—4 tentacles; but they are a great deal more reduced than is apparent from his pictures, 

 and agree better with the drawings published by Jaderholm (1909, PI. 2, Fig. 10— 11). However, 



