434 Mr. W. G. Ridewood on 



is given on pages 66-77 of the 'Terra Nova' Report (i6), 

 together with a list of all recorded specimens and details of 

 the localities from which they were severally obtained. A 

 key for the ready identification of tlie various species was 

 published last year in the ' Annals and Magazine of Natural 

 History' (iS). 



The first-recorded specimens of Cephalodiscus densns were 

 obtained on the Swedish South-Polar Expedition of 1901- 

 1903, and were described by Andersson in 1907 (2) ; other 

 specimens have since been secured on tlie British Antarctic 

 ('Terra Nova') Expedition of 1910-1913 (16), and on the 

 Australasian Aiitaretic Expedition of 1911-1914 (17). It is 

 of particular interest now to be able to record the dredging 

 of material of this species as far back as 1874 — that is to say, 

 two years before the classical material of Cephalodiscus 

 dodecaloplius was obtained. While, however, the specimens 

 that form the subject of the present communication must be 

 admitted to be of exceptional interest, by I'eason of tlie fact 

 that they were obtained earlier than tiiose of Cep//alodificus 

 dodecaloplius, they nevertheless do not constitute the tiist 

 specimens of Cephalodiscus dredged, for it is almost certain 

 that material of Cephalodiscus nigrescens was obtained on the 

 'Erebus' and 'Terror' Antarctic Expedition in either 1841 

 or 1842 (15). 



Previously recorded material of Cephalodiscus densus shows 

 that the species has a wide distribution in the Antarctic seas, 

 specimens having been obtained in Russ Sea by the ' Terra 

 Nova' Expedition, off Giaiiam Land by the Swedish South- 

 Polar Expedition, and off Queen J\hiry Land by the Austral- 

 asian Antarctic Expedition. It is interesting to be able now 

 to add to these a fourth locality — Kerguelen Island. Should 

 Gravier''s species Cephalodi.scus anderssoni prove to be the 

 same as Andersson's Cephalodiscus densus, the known distri- 

 bution of the species is not thereby greatly extended, for the 

 localities from which Gravier's material and Andersson's 

 material were obtained are on the west coast and east coast of 

 Graham Land respectively — see map, pi. vi. in ' Terra Nova' 

 Report (16). 



The material now under consideration is contained in two 

 bottles, and, though all was obtained from the same locality — 

 Kerguelen Island, Stat. 149, January 1874, — the subsequent 

 histories of the two parts of it prove to have been different. 

 The larger bottle contains seven fragments, four of which 

 might iiave come from the same colony ; these are of a sandy- 

 grey colour. The other three pieces are of a rather more 

 rufous tint; they are "dead/^ with no zooids in the tubes, 

 and the common coenoecial substance between th^ tubes is 



