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



PRIBILOF ISLANDS. 



By William Emerson Eitter, Ph. D., 

 Associate Professor of Zoology, University of California. 



The Tuuicata liere described reached me iu two installments. The first w^as 

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

 July, 1896; the second by Messrs. E. E. 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, Dendrodoa tuberculata, B. 

 suhpedunculataj Aplidiopsis jordani, and Polyclinum glohosum. It 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 elegans, Herdman. 

 Styela greeleyi. New species. 

 Dendrodoa tuberculata. New species. 



subpedunculata. New species. 

 Ascidiae Compositae : 



Polyclinum gloiosum. New species. 

 pannosuni. New species. 

 Aplidiopais jordani. New species. 

 Amaroucium, Tcincaidi. New species. 



pribilovense. New species. 

 snodgrassi. New species. 

 Synoicum irregulars. New species. 



Facts 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, Dendrodoa and Synoicum, are, so 

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

 species, Boltenia elegans is known only from the extreme North Pacific ; ApUdiopsis 

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

 Amaroucium pribilovense and A. snodgransi have apparently rather closer affinities 



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