CEUSTACEA. 



YII-SCHIZOPODA. 



By W. M. Tattersall, M.Sc. 



(8 Plates.) 



The collection of ' Discovery ' Schizopoda is a large one from the point of view of the 

 number of specimens it contains, considerably over ten thousand, including larvae, 

 having been collected. By far the majority of these specimens, nearly ten thousand, 

 however, belong to one species, and the total number of species reaches thirteen. The 

 collection is in a generally excellent state of preservation, though many specimens have 

 undoubtedly suffered from being frozen after coming out of the water and from the 

 subsequent thawing before preservation. 



In the preliminary notice of this collection (Holt and Tattersall, 1906 (l)*) ten 

 species were noted, of which five were absolutely new, two were only known under 

 manuscript names given to them by Dr. Hansen from the collections of the ' Belgica ' 

 Antarctic Expedition, while the remaining three were already described forms. 



Since the publication of that notice further material has come to hand, collected 

 on the homeward journey of the ' Discovery.' It contained two species of Euphausia 

 not included in the earlier material, one, an immature form which was too young to 

 be specifically identified ; the second, a species very close to E. lucens, Hansen 

 {= E. splendens, G. 0. Sars), but which Dr. Hansen has kindly informed me is distinct, 

 and will be described by him in a forthcoming paper. A re-examination of the two 

 specimens which in the preliminary note were referred to Mysis inaxima, 

 Hansen (MS.), has shown that they represent in reality two very closely allied 

 species, the second of which will also be described by Dr. Hansen in a future work. 



Previous to the recent activity in South Polar exploration only three expeditions 

 to the Antarctic had brought back zoological material from which Schizopoda were 

 recorded. Dana (1852) in his great work on Crustacea records two species from 

 Antarctic waters {i.e., south of lat. 60° S.) viz., Euphausia superba and Eucopia australis. 



H.M.S. ' Challenger ' in 1874 collected, in the same region, Euphausia superba, 

 E. murrayi, E. antarctica, Thysanoessa macrura and a species of Pseudomma, 

 doubtfully referred to P. sarsi by Prof. Sars, who described the Schizopoda of that 

 expedition. The second and third species .in this list are, however, only synonymous 

 with the first, so that the real total of 'Challenger' Antarctic species is three. 



* These dates refer to the list of Memoirs on p. 38. 



