174 THE VOYAGE OF H.M.S. CHALLENGER. 



however, by its smaller size, lesser number of cirrus-joints, and by the different proportions 

 in the lengths of the first two pairs of pinnules. Like Antedon prolixa, too, it ranges from 

 shallow water down to 700 fathoms; but it has a much more extensive geographical range. 



Fischer 1 has recently come to the conclusion, which I believe to be an erroneous one, 

 that the specimens which were described by Duncan and Sladen 2 under the name Antedon 

 prolixa are in reality but " ausgewachsene Exemplare " of Antedon sarsii, auct., i.e, 

 of Antedon tenella. Two of the four Comatulse which he obtained at Jan Mayen 

 clearly belong, as he himself states, to Antedon prolixa, as defined by Sladen. The 

 length of an incomplete arm in the larger one is 120 mm. The cirri, composed of 

 twenty-eight to forty-three joints, vary in length from 20 to 60 mm. ; the first pinnule 

 with twenty-eight joints is 14 mm. long, and the second with twelve joints reaches only 

 4"3 mm. 3 It appears from these numbers that Fischer's larger specimen is somewhat 

 better developed than Sladen's type, with which it is evidently identical. Fischer has 

 further compared it with the two individuals which were obtained in the Barents Sea by 

 the " Tegetthoff," and were referred by Dr. E. von Marenzeller to Antedon sarsii. 4 

 Fischer's conclusion is expressed in the following passage, — " Wenn man nun erwagt, 

 dass mit Ausnahme der durch die Grossenverhaltnisse bedingten Unterschiede (das 

 grossere der von Marenzeller beschriebenen Exemplare hatte Arme von nur 80 mm. Lange) 

 namlich die geringere Anzahl von Eanken-Gliedern, — sonst keine Abweichungen zu 

 verzeichnen sind, so muss man nothwendigerweise zu der Uberzeugung gelangen, was ich 

 ubrigens an der Hand der spater zu beschreibenden Jugendzustande des Weiteren ausfiihren 

 werde, dass unter Antedon prolixa, Sladen nur ausgewachsene Exemplare von A. Sarsii, 

 welche bislang noch nicht erschopfend beschrieben waren, zu verstehen sind." 



The largest cirri of the "Tegetthoff" specimens have thirty-three joints and reach 

 37 mm. long. These dimensions are altogether exceptional for Antedon tenella, in the 

 Scandinavian examples of which there are usually not more than eighteen or twenty 

 cirrus-joints, while there may be about twenty-five in those from the Kara Sea and the 

 Fseroe Channel, and twenty-eight or thirty in the American variety, with a maximum 

 length of 24 mm. 5 I cannot help suspecting therefore that the "Tegetthoff" specimens 

 may really be the young of Antedon prolixa. Dr. von Marenzeller was kind enough to 

 send them to me for examination in 1881, and I have hitherto regarded them as he 

 seems to have done, viz., as abnormal forms of Antedon sarsii (tenella). At the 

 time I examined them I was unacquainted with Antedon prolixa, and the possibility of 

 their being the young forms of this type never occurred to me. But in the six 

 years which have passed since then I have seen many examples both of Antedon 



1 Eckinodermen von Jan Mayen, Die Usterreiche Polarstation Jan Mayen, Bd. iii., Wien, 1886, p. 30. 



2 Op. cit, p. 77, pi. vi. figs. 7-10. 



3 This is accidentally printed as 43 mm. in Fischer's paper. 



4 Denkschr. d. k Alcad. d. JViss. Wien, 1877 (1878), Bd. xxxv. p. 381. 



5 Figs. 3, 4 on PI. XXXI. represent the average cirri of the Faeroe Channel and American varieties respectively. 



