346 DISCOVERY REPORTS 



oblique distal border closely follows the hinge line of the opercular valve. Most of the 

 aberrant scuta are worn and chipped, but the differences in the lumen are such that they 

 could not be derived from normal ones merely by wear. The difference is definite, and 

 there appear to be no intermediate specimens, but as no other distinction has been 

 noticed and the variability of scuta is well known, I have not separated these specimens 

 from N. drygalskii. In the material from St. TN 194 the two forms are present in 

 almost equal quantities, and St. TN 339 also yielded both. From St. TN 316 only the 

 aberrant type was obtained. 



N. drygalskii seems to be much more common than N. vanhoffeni in the regions in 

 the far south visited by the ' Discovery ', as well as being found at South Georgia where 

 N. vanhoffeni has not been recorded. At St. 1652 (Ross Sea) the 'Discovery' obtained 

 fifteen luxuriant colonies of TV. drygalskii. The largest was 16 cm. long and 1 1 cm. across 

 at its thickest point (PI. VI, fig. 6), and several of the others were only a little smaller. 

 In each colony the rootlet bundles form quite a stout stalk, ending in a tuft of rootlets 

 to which little black stones and grit adhere. 



N. vanhoffeni is only represented from a few stations and the material is sparse and 

 rather fragmentary. In this species also the rootlets form a stalk, but no complete colony 

 showing the attachment has been seen. 



Testes of the usual type are to be seen, consisting of very numerous clusters of cells 

 filling the proximal part of the body-cavity. Ova of moderate size are sometimes present 

 in the same zooecia as the spermatic tissue. In the material from St. 371 (14 March 

 1930) many zooecia have the ovicell empty and a large egg in the body-cavity, while in 

 others the egg has passed into the ovicell and, in some, has begun to segment. The 

 specimen obtained by the National Antarctic Expedition in McMurdo Sound on 

 13 February 1902 had three ancestrulae of the same species attached to it. They are 

 vase-shaped and have eight or nine spines and are attached by a tubular prolongation 

 of the proximal end (Fig. 1 1 A). Succeeding zooecia are typical except for the absence 

 of frontal avicularia. 



4. Notoplites vanhoffeni (Kluge). Fig. 10 A, B. 



Scrupocellaria vanhoffeni Kluge, 1914, p. 610, pi. xxvii, fig. 6. 



Notoplites vanhoffeni Harmer, 1923, p. 353. 

 Station distribution. Antarctic: Weddell Quadrant, St. 190. 



Geographical distribution. Palmer Archipelago (Discovery); Wilhelm II Land (Kluge); 

 Oates Land (Terra Nova); Ross Sea (National Antarctic Expedition; Terra Nova). 



Comparison of this species with Notoplites drygalskii will be found on pp. 342, 340 (key). 

 The internal spine is stout, and may be branched almost at its base, appearing paired 

 (Fig. 10 B). 



5. Notoplites elongatus (Busk). Figs. 12 A, B, 13 A. 



Cellularia elongata Busk, 1884, p. 19, pi. iii, fig. 3. 



Notoplites elongatus Harmer, 1923, p. 351. 

 Station distribution. Sub- Antarctic: South Indian Ocean, Sts. 1562, 1563. 

 Geographical distribution. Kerguelen (Busk); Marion Island (Discovery; 87. 12.9.97 B). 



