Ascidiacea 5 b 



Trididetnnum tenerum (Verrill) 



1896. Didemnoides variable. Huitfeldt-Kaas, p. 5. 



See Van Name (1910, p. 385) for description and literature. 



Station 23, one colony. 



No spicules were found in the single colony obtained. Colony 34 X 18 X" 

 7.mm.; individuals about 1-5 mm. long; oral aperture 6-lobed; the atrial without 

 languet on a tubular siphon and indistinctly lobed; three rows of stigmata, 

 about 12 in each row; two dorsal languets on transverse vessels of left sidei 

 testis with coiled vas deferens on outer surface. 



This is an arctic species, which is doubtless circumpolar, the present record 

 tending to connect the known distribution in northern European seas and the 

 Asian arctic ocean with that along the east coast of America from Newfoundland 

 to Cape Cod. 



Didemnutn albidutn (Verrill) (?) 



See Van Name (1910, p. 378 as Tetradidemnum albidum) for description 

 and literature. 



Sta. 23, 3 colonies. 



The very small size of the colonies in the collection has prevented a positive 

 identification. In the character of the spicules and in such details of the struc- 

 ture of the zooids as could be determined they agree with the description of this 

 species given by Nan Name. 



This is a very definite extension of the known distribution of this species, 

 which hitherto has been found only in the Atlantic portion of the arctic and 

 subarctic from Spitsbergen and the Murman coast to Davis strait and Cape 

 Cod. Hartmeyer has, however, recently (1921, p. 87) reported it from the 

 Siberian arctic coast and Bering strait. 



Ascidiopsis prunum (0. F. Miiller) 



See Van Name (1912, p. 599 as Phallusia prunum) for description and liter- 

 ature. 



Sta. 41, 4 specimens. — North Greenland, coll. P. H. Sorensen, U.S. Nat. 

 Mus. No. 6632, 1 specimen. 



This is a widely distributed circumpolar form. As Hartmeyer has sur- 

 mised, it occurs in the northern Pacific, and I expect to publish shortly an 

 account of its synonymy and distribution there. 



Ascidiopsis dijmphniana (Traustedt) 



1886. Phallusia dijmphniana, Thaustedt, p. 424. 



1903. Ascidia dijmphniana, Hartmetek, p. 293. 



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

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



As this species has not been very thoroughly described, an account of this 

 well preserved specimen from Franz Josef land is desirable. 



In size, 34 X 24 X 14 mm. The animal is oblong in shape and is attached 

 by the posterior part 'of the left side. The surface is extensively wrinkled and 

 shows scattered, minute papilla; • 1 mm. in diameter, and from • 1 to • 3 mm. 

 long, in which terminate many of the vessels which are abundant throughout 

 the test. These papillae are best developed and most numerous near the aper- 

 tures, but are present over the entire unattached portion of the test. The 

 apertures are both at the anterior end, the oral in the centre and the atrial at 

 the dorsal angle. The lobes are provided with many scattered, short papillae, 

 and number seven for the oral and six for the atrial. 



