Ascidiacea 7s 



Chelyosoma macleayanum Brod. and Sow. 



See HARTMEYER (1903, p. 269) and VAN NAME (1912, p. 591) for descrip- 

 tion and literature. 



Station 22, 2 specimens. Station 23, 11 specimens. 



This well known species is a characteristic arctic circumpolar form, but is 

 usually found in very-small numbers. The specimens here reported show the 

 usual large size that is attained by this species in the arctic, as compared with 

 the subarctic. All but two of the specimens were from 16 to 37 mm. long. 

 Their growth has been studied (Huntsman, 1921). 



Molgula septentrionalis Traustedt 



For literature references on this species see VAN NAME, 1912, p. 478, and 

 Redikorzew, 1916, p. 94. 



Aberdare channel, east of Alger island, Franz Josef land, June 1901, 

 Baldwin-Ziegler expedition, U.S. Nat. Mus. No. 6639, 1 specimen. 



This species has previously been recorded from Spitsbergen, as well as 

 from other points in the Atlantic portion of the arctic from Novaya Zemlya 

 (Redikorzew, 1916, p. 94) to Hudson bay (Huntsman, 1922). 



Cystingia griffithsii MacLeay 



1825. Cystingia griffithsii, MACLEAY, p. 541. 

 1842. Clavelina chrystallina, MOLLER, p. 95. 



Per a, Molgula, s. Caesira crystallina, auct. var. 



Station 23, 5 specimens. Station 37 b, 14 specimens. Station 41, 4 speci- 

 mens. Station 43 a, 1 specimen (test only). 



.In 1825 MacLeay described three species of Ascidians that had been col- 

 lected by W. N. Griffiths at Winter island in Fox channel on Capt. Parry's 

 second arctic voyage. Two of these are well known arctic forms (Boltenia and 

 Dendrodoa) . The third, which he called Cystingia griffithsii, has not since been 

 recognized among arctic or other material of Ascidians. It has been considered 

 as belonging to the family Tethyidae (Cynthiidae) , and to be near the genus 

 Fungulus. Hartmeyer has, however, (1903, p. 188) called attention to the 

 fact that an organ of this species described and figured by MacLeay resembles 

 the renal organ of Caesirids (Molgulids). As this form was obtained in the 

 same general region as that explored by the Canadian Arctic Expedition, it 

 seemed probable that Cystingia might be found in the material brought back by 

 that Expedition. After working over that material, I turned to MacLeay's 

 figures and description of Cystingia, and it was at once apparent that MacLeay's 

 Cystingia griffithsii was none other than a somewhat unusual specimen of the 

 now well known Caesira (Molgula) crystallina, first described by Mb'ller in 1842 

 from Greenland. 



MacLeay's description and .figures were not sufficiently clear and accurate 

 to have prevented error concerning the systematic position of this species. 

 The unusual structure of the stalk of his single specimen has perhaps contributed 

 to the failure in the identification of his species with C. crystallina. One of the 

 specimens collected by Johansen has a similar stalk, with the attached area 

 and "roots" along one side instead of being, as is usual, at the distal end. Indi- 

 viduals with intermediate conditions were also brought back by Johansen. 



