4 B Canadian Arctic Expedition, 1913-18 



Station 37 6. Inner harbour at Bernard harbour, Dolphin and Union strait, 

 Northwest Territories, 2-3 fathoms, sandy mud, August 25, 1914. 

 Cystingia griffithsii. 



Station 37 e. Inner harbour at Bernard harbour. Dolphin and Union strait. 

 Northwest Territories, about 2 fathoms, sandy mud, September 1, 1914. 

 Rhizomolgula glohularis. 



.Station 41. Outer harbour at Bernard harbour, Dolphin and Union strait. 

 Northwest Territories, about 10 metres, sandy mud, July 20, 1915. 

 Ascidiopsis prunum. 

 Cystingia griffithsii. 

 Rhizomolgula glohularis. 



Station 43 a. Dolphin and Union strait, Northwest Territories, about 100 

 metres, sandy with pebbles, September 13, 1915. 

 Cystingia griffithsii. 



Station 43 h. Dolphin and Union strait. Northwest Territories, 50-60 metres, 

 sandy mud with pebbles, September 14, 1915. 

 Cnemidocarpa rhizopus. 



Station 43 c. Dolphin and Union strait. Northwest Territories, 20-30 metres, 

 gray mud and stones, September 14, 1915. 

 Styelopsis sp. (?). 



Station 50 d. Young point. Dolphin and Union strait, Northwest Territories. 

 0-1 fathom, rock, July 21, 1916. 



Styelopsis sp. (?) 



Aplidium spitzbergense Hartmeyer 



1903. Aplidium spitzbergense, Habtmeyer, p. 341. 



1908 b. Amaroucium sarsi, Bjerkan, p. 92. 



1912. Aplidium spitzbergense, Huntsman, p. 137. . 



West coast of McClintock island, Franz Josef land, (80° 22' N. lat.), July 

 1902, Baldwin-Ziegler expedition, U. S. Nat. Mus. No. 6640, 2 colonies. 



In the smaller colony (20 X 15 X 8 mm.) the zooids are at most 5-7 mm. 

 long, and no eggs or embryos could be found. In the larger one (28 X 20 X 

 10 mm.) the zooids were as long as 10 mm., and both eggs and embryos were 

 observed. The difference in the length of the zooids appears to be due wholly 

 to the postabdomen, the abdomen and thorax being virtually of the same length 

 in individuals from both colonies. 



There are four rows of stigmata with about twelve stigmata in each row, 

 three dorsal languets, and three gastric folds. The languet in front of the atrial' 

 aperture varies much in length and may be either simple or forked. 



There seems to be no essential difference between Bjerkan's species, which 

 he places in the genus Amaroucium, and that described by Hartmeyer. The 

 differences hitherto given as a basis for separating the two genera are not suffi- 

 cient for dividing the species distinctly into two natural groups, and revision is 

 much needed. 



The distribution of this species is similar to that of a number of other 

 Ascidians and may be defined as being nearly throughout the Atlantic arctic 

 and subarctic regions. 



