XIX.-A CONTRIBUTION TO THE KNOWLEDGE OF THE TUNICATA OF THE 



PRIBILOF ISLANDS. 



By WiLMAM Emerson Eitter, Ph. D., 

 Aaaociate Professor of Zoology, University of 'California. 



The Tunicata here described reached me in two installments. The first was 

 collected by President Jordan himself on Lukanin Beach, St. Paul Island, during 

 July, 1896; the second by Messrs. E. B. Snodgrass, Trevor Kincaid, and A. W. Greeley 

 from July to September, 1897. This second installment contains specimens gathered 

 from various points, which will be found specified in connection with the descriptions 

 of the species. The first lot contained four species, viz, Bendrodoa tuberculata, D. 

 subpedwnculata, Aplidiopsis jordani, and Polyclinum globosum. Jt is perhaps significant 

 that the last two species are not represented in the second installment, even though this 

 contains a much larger number of specimens all told and is the result of a considerably 

 longer continued and wider range of collecting. President Jordan informs me that 

 the summer of 1896 was particularly stormy at the Pribilofs. The following is a list 

 of the species contained in the collection : 



Ascidiae Simplices: 



Boltema elegams, Herdman. 

 Styela greeleyi. New species. 

 Bendrodoa tubercwlata. New species. 



subpedii/noulata. New species. 

 Ascidiae Compositae : 



PolyeUnum globosum. New species. 

 pannosum. New species. 

 ApUdiopsis jordani. New species. 

 Atnaroudium Mncaidi. New species. 



priiilovense. New species. 

 snodgrassi. New species. 

 Synoieum irregulare. New species. 



Pacts of some interest relating to the geographical distribution are brought out 

 by considering the species here described in connection with other known far northern 

 tunicates. Of the genera represented, two, viz, Bendrodoa and Synoicum, are, so 

 far as we now know, confined to the Arctic or North Atlantic oceans. Of the other 

 species, Boltema elegans is known only from the extreme North Pacific; Aplidiopsis 

 jordani has as its nearest ally A. sarsii, Huitfeldt-Kaas, from Lofoten Islands ; and both 

 Amaroucium pribilovense and A. snodgrassi have apparently rather closer affinities 



511 



