128 "TERRA NOVA" EXPEDITION. 



communication with the lumen of the rhynchodseum. The figures given, however, 

 are not altogether convincing ; ;ui<l on re-examining the material (which is not 

 conspicuously well preserved), I have formed the conclusion that the "ampullae" 

 are to a certain extent artificial results of the contraction of the wall of the 

 rhyncliuda-um. They are, in fact, a kind of "hernia" of the lining epithelium, 

 which is here and there pushed outwards between the muscles, thus forming minute 

 diverticula still in communication with the main cavity of the rhynchodseum. They 

 do not occur in all the series of sections examined, and are not, therefore, an 

 essential feature of the species. Moreover, their outer communications with the 

 Mood-sinus are, I believe, imaginary. In no case have I detected any actual 

 opening, and though they sometimes come very near to the surface. I believe that 

 this appearance is entirely due to artificial causes. 



Having already stated my conviction that Linen-* /tanvi'iii and Eujmlia /niiuii'tti 

 are synonymous with L. i-orruyatus, I may perhaps be permitted further to add that I 

 feel some doubt as to whether Cerebratulus charcoti, Jonbin, should not come under 

 the same category. The author's description (1908) does not appear to me to show 

 any very satisfactory grounds for its separation ; no description or figures of its internal 

 anatomy are given, and the main points upon which the distinction of the species 

 is based are (l) the marked flattening of the posterior end of the body : (2) certain 

 verv vague features of colour ; and (3) the great length and attenuation of the head. 

 Now (1) the flattening of the body, as I have attempted to show above, occurs in 

 specimens which I cannot regard as other than L. corrugatus ; (~2) colour, in spirit - 

 preserved material, can hardly be said to have any importance at all, being often 

 affected by the pigments of other specimens, &c., which may have been immersed 

 in the same spirit ; while (3) the comparative length of the head, mouth, <., in 

 these worms is a matter obviously dependent upon the growth of the individual 

 and the mode of fixation or preservation employed, and may be extremely variable 

 in preserved specimens of the same species. 



Taking all these facts into consideration, I think the evidence points to the 

 ((inclusion that in all four cases [Linens I'liri'injatnn, Jjni'iix hanseni, Cerebratulus 

 i-//n>'i'i>f/\ and Kni>li, punnetti) we are dealing with one and the same species, and that 

 this is the form originally described by M'Intosh (1H7(>) under the name of Linnix 

 corrugatus. 



DISTRIBUTION. 



By the inclusion of the several species above-mentioned in the sviionvmv of 

 I., i-orriti/ttftix, the range of the latter is seen to extend to the western as well as the 

 eastern side of the subantarctic regions. The specimens determined by M. Joubiu as 

 Cerebratulus <-<>rrn<i<itnH and ('. r/tnrcufi came from Booth-Wandel Island. I have also 

 to add that some immature specimens brought from Cumberland Bay, South Georgia, 

 by the late Major (4. E. II. Barrett-Hamilton's Expedition, 11)13-1914, belong, in 



