TRICELLARIA 359 



fuegensis (54. n . 15.262) that it must have been drawn from it. The basal parts of the 

 colony differ from the corresponding parts of true Menipea patagonica (Fig. 6 A) in the 

 shape of the ancestrula ; in the smaller number of zooecia in the first two internodes ; 

 in the more or less frontal origin of the rootlets ; and in the presence of scuta, of which 

 the bases now remain. In the specimen figured by Busk the first internode consists of 

 one zooecium. In the Discovery material from St. WS 84 (24 March 1927), and speci- 

 mens belonging to the Hamburg Museum (B. 1025) and the U.S. National Museum, 

 there are three zooecia in the first internode. The ancestrula figured by Jullien (1888, 

 pi. vii, fig. 8) is a little taller than those examined by me. 



3. Tricellaria sp. 



Station distribution. Not represented in the Discovery collections. 



Geographical distribution. Challenger St. 299, off Valparaiso, 3953 m. (99.7. 1 .4564). 



Description. Zoarium biserial, bifurcation of Harmer's type 9 with one branch (the 

 one including zooecia CG) at each bifurcation unjointed. 



Zooecia raised distally, opesia more or less oval with thin raised edge, tubular proximal 

 portion forming more than half and often more than two-thirds of length of zooecium, 

 frequently with faint transverse striations. 



Spines: 2 to 4 long curved spines arranged in an oblique row running from outer 

 distal corner across basal surface of projecting distal end of zooecium; frequently a 

 stout straight spine on raised edge of inner border of opesia towards proximal end, 

 directed frontally. 



Scutum absent. 



Rootlets springing laterally from portion of zooecium C proximal to joint and from 

 proximal part of some other zooecia ; not applied to surface of colony. 



Avicularia and ovicells not seen. 



Remarks. The single small specimen of this species was found in the Busk Collection, 

 labelled Bicellaria. It was only discovered after some of the books and specimens 

 necessary for its proper comparison with known species had been stored for safety 

 during the war. It is, however, certainly distinct from seven of the eight species included 

 in Tricellaria by Harmer (1923, p. 354). The description of the eighth species, T. pribilofi, 

 is not available. It is probably also distinct from Harmer's two additional species (1926, 



PP- 356, 358). 



In its bifurcation, with one branch unjointed, Tricellaria sp. resembles T. sympodia 

 (Yanagi and Okada, 1918, p. 410, Japan 457-5 m.), and T. aquilina and T. scalariformis 

 Harmer (1926, Malay Archipelago 2081 m. and 270-469 m. respectively). 1 It differs 

 from all three in the absence of avicularia, in its free rootlets and in the number and 

 arrangement of its spines. It appears to be most nearly related to T. aquilina which it 

 resembles in the separation of the bases of zooecia F and G on the basal surface of E. 

 The long spines on the inner margin of the opesia may be on zooecium A or B, or 

 (in one instance) on one of the zooecia on the undivided sympodial branch. They are 



1 See Addendum, p. 501. 



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