58 DE. p. H. CABPENTEE ON SOME AllCTIC COMATULiE. 



A. Sarsii (tenella) are as follows : — 1, Size ; 2, the Cirri ; 

 3, tlie Eadials ; 4, the Shape of the Arm-joiuts ; 5, the 

 Syzygies. 



1. The Scandinavian variety oiAntedon tenella is much smaller 

 and less robust than that found in the deeper water of the At- 

 lantic, both east and west. The examples dredged by the ' Blake ' 

 off the New England coast are the largest which I have seen ; 

 but the disk is not more than 7 ram. in diameter, while the 

 maximum length of an arm scarcely reaches 70 mm. On the 

 other hand, Fischer's largest individual o£ A. prolixa from Jan 

 Mayen has a disk 10 mm, in diameter, and he measured one arm 

 as 120 mm. long, adding " Es fehlt jedoch ein gutes Stiick von 

 der Spitze des Amies." This difference in size between the two 

 types would, of course, be unimportant alone ; but taken together 

 with those other differences now to be described, it may, I think, 

 be regarded as affording a good specific character. 



2. The Scandinavian variety of Antedon tenella usually has but 

 18 or 20 cirrus-joints, while there may be 25 in those from the 

 Faroe channel and Kara Sea, and 28 or 30 in the American 

 variety, with a maximum length of 24 mm. These dimensions 

 are very different from those of the individuals wliich have been 

 referred to A. p-olixa, as will be seen from the following 

 Table :— 



Antedon tenella Longestcirriof American variety 24 mm., with 30 joints. 



{Sarsii, auct.). 



'Antedon prolixa. 



'Tegetthoff' Longest cirri 37 mm., with 33 joints. 



Jan Mayen Longest cirri 60 mm., with 43 joints. 



Sladen's types...,,. Longest cirri 60 mm., with 45 joints. 



'Porcupine' ...... Longest cirri 50 mm., with 45 joints. 



' Varna ' (immature). Longest cirri 35 mm., with 35 joints. 



' Voringen' ..... Longest cirri 35 mm., with 40 joints. 



A specimen from i 



Finmark in the \ Longest cirri 35 mm., with 41 joints. 



British Museum J 



See also the measurements given on p. 176 of the Report on the ' Challenger ' 

 Comatula;. 



3. If Fischer be right in his supposition that Antedon prolicca 

 is merely the fully grown form of A. Sarsii (tenella), one would 

 of course expect that the individuals referred to the latter type 



