The Tunicata of the Scottish National Antarctic Expedition. By W. A. Herdman, 

 D.Sc., F.R.S., Professor of Zoology in the University of Liverpool. (With 

 One Plate.) 



(MS. received January 8, 1912. Read February 19, 1912. Issued separately July 3, 1912.) 



So far as regards number of individuals, and their size, this is one of the largest 

 collections of Ascidians brought back in recent years from Antarctic seas. It contains 

 almost exactly the same number of species of ASCIDIACEA (Ascidise Simplices + Asddiae 

 Composite) as the Discovery collection viz. fifteen or sixteen but whereas in the 

 latter collection nearly all the species were represented by single specimens, in the 

 Scotia collection most species can show long series of individuals in all there are about 

 two hundred specimens, as against the thirty-three brought home by the Discovery. 



The sixteen species in the present collection represent almost as many genera, and 

 half a dozen families. The systematic arrangement is as follows : 



ASCIDIACEA. 



Family MOLGULID.E. 



Paramolgula gregaria (Lesson). 

 Paramolgula horrida (Herdman). 



Family CYNTHIIDJE. 



Boltenia legumen, Lesson. 

 Fungulus-antarcticus, n. sp. 

 Halocij/tthia setosa, Sluiter. 



Family STYELID.*:. 

 Styela lactea, Herdman. 

 Styda paessleri, Michaelsen. 

 Synstyela incriistans, Herdman. 



Polyzoa opuntia, Lesson. 

 Goodsiria placenta, Herdman. 



Family ASCIDIID.E. 

 Ascidia charcoti, Sluiter. 



Family DISTOMID.E. 



Colella pedunculata (Q. and G.). 

 Holozoa cylindrica, Lesson. 



Family POLYCLINID.E. 



Polyclinum complanatum, Herdman. 

 Amaroucium distomoides, Herdman. 

 Amaroudum sp. 



It is interesting to notice how greatly some of these recent collections from the far 

 South differ from one another in the species represented. The following table which 

 gives only the sixteen species in the Scotia collection shows that only one form 

 (Halocynthia setosa) from that collection was also taken by the Discovery, whereas ten 

 species were taken by the Challenger, eight by the Hamburg Magellanic and South 

 Georgia Expedition, and five by the French Antarctic Expedition under Charcot. This 

 can be explained to some extent, at least, by the precise localities visited : the Scotia, the 

 OiaJlenger, and the Hamburg collections were largely made in the Magellan and Falk- 

 lands neighbourhood, while the other three collections were mainly from farther south. 



(REPRINTED FROM THE TRANSACTIONS OF THE ROYAL SOCIETY OF EDINBURGH, VOL. XLVIII., pp. 305-320.) 



