i:;r, "TERRA NOVA" EXPEDITION. 



547 metres at Station 355, 77 40' S., KK! 7 ' 8' E. (M<Alurdo Sound). Tin- host is 

 unfortunately unknown, the worm having been found loose. 



The ' Terra Nova " specimen is larger than any described liy v. Stummer-Trauufels, 

 having a length of S mm. The lateral margins are bent downwards so as to make the 

 dorsal surface verv convex, lint when flattened out the body is seen to have a breadth 

 of nearly 9 mm. 



A narrow, translucent marginal area is rather sharply marked off from the very 

 thick bodv-disc, its border is slightly crenulated and presents distinct concavities at the 

 {interior and posterior extremities. 



As in the type specimens the dorsal integument, except in the marginal area, is 

 covered with small, closely set tubercles, too small to be distinguished by the naked 

 eye, but giving the skin a very characteristic " warty" appearance when viewed under 

 a, low power of the microscope, v. Stummer-Traunfels describes the ventral surface 

 as smooth : in the specimen before me, however, the ventral integument is sculptured 

 in a similar but less pronounced manner than that of the dorsal surface. 



The ten pairs of cirri arise from little notches in the margin, they are bilaterally 

 symmetrical in their arrangement and approximately equidistant from one another, 

 except in the case of the first and last pairs, the members of which are much further- 

 apart than the others. 



The structure of the parapodia, suckers, and other organs is exactly as in the type 

 specimens. 



Myzostoma r//*ti<:i>l<i, v. Graff. 



3Iiiz(ixh>in(( cysticolum, v. Graft', "Challenger" Rep., vol. x, ISM, j>. (i6. 

 ,, v. Stummer-Traunfels, op. <//., p. 7. 



,, var. orientale, McClendon, Hull. Amer. Mus. Nat. Hist., vol. xxii, 



1906, p. 120. 



,, ,, sub-sp. cystihymenodes, McClendon, Proc. U.S. Nat. Mus., vol. xxxii, 



1907, p. Go. 



1 have referred all the cysticolous specimens collected by the "Terra Nova" 

 Expedition to this very interesting species. M. cysticola was first described by 

 v. ({raff in 1884 from a number of specimens forming small cysts (1-3 mm. in length) 

 on the arms of Artiiionietrn 'meritl'mnnlix, var. i-iu'/niifii, from Brazil and Grenada. 



The species was redescribed in l'.)0(i by McCleudon from a single specimen on 

 Aiiti'ilnn discoidea obtained by the "Albatross" Expedition off the eastern coast of 

 Japan ; on account of the large size of this cyst (5 mm. in length) and of certain slight 

 differences in structure it was referred by the author to a new variety orit'iitnli'. 



v. Stummer-Traunfels, in his report on the "Discovery" collection, points out 

 that the differences between McClendon's and v. ({raff's specimens are undoubtedly due 

 to individual variation, and includes two large cysts (5 mm. and ()"1 mm. in length) 

 from Aiiti'ilon iiili-iititi in this widely distributed species. The cysts and the worms 

 enclosed in them agree in most particulars with the tvpe specimens, apart from size the 



