. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. TETRAXONIDA 299 the dermis is supported by a tangential layer of tornota. Anisochelae and bipocilla are present. In all respects, these specimens appear to be conspecific, despite obvious differences in the shape and size of the acanthostyli and tornota and in the shape of the bipocilla; and this is even more clearly shown when they are compared with the specimens re- corded under the various names included above as synonyms of /. chelifer. Nevertheless, it must be confessed that the species is
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. TETRAXONIDA 299 the dermis is supported by a tangential layer of tornota. Anisochelae and bipocilla are present. In all respects, these specimens appear to be conspecific, despite obvious differences in the shape and size of the acanthostyli and tornota and in the shape of the bipocilla; and this is even more clearly shown when they are compared with the specimens re- corded under the various names included above as synonyms of /. chelifer. Nevertheless, it must be confessed that the species is an unusually variable one. The variation in ex- ternal form is not particularly marked, but in the spicules it is, although the series of transitions which it is possible to construct leave no doubt as to the identity of all the. t t' w Fig. 22. lophonproximum (Ridley): showing variation in ends of tornota. a, I. chelifer ostia-magna, Wilson (type); b, I. chelifer, Ridley and Dendy (co-type: 87. 5. 2. 157); c, /. chelifer, Ridley and Dendy (type); d, I. chelifer, Ridley and Dendy (Lambe's specimen); e, G iog\f, I. indentatus, Wilson (type); », /. lamella indivisus, Wilson (type); /;, /. lamella, Wilson (type); i, I. pattersoni (Bowerbank), Ridley and Dendy (Challenger Sts. 308 and 3ii);y, /. chelifer, Ridley and Dendy (Thiele's specimen); k, D 255; l-l", D256; m, D 251; n, D739; 0, D 740; p, D 257; q, D 254, D 258; r, D431; s, D 252 ;<,/',£) 837; u, D 430; v, Alebion proximum, Ridley (type); ro, lophon proximus (Ridley), var. reticularis, Hentschel. All figures x 1200. Figs. a,f,g,h after Wilson; fig. d after Lambe; fig. j after Thiele. Fig. w from a preparation from the type. specimens with a single species. Some of the variations can be correlated, but only vaguely, with increase in size, but nowhere is there so clearly marked a sequence as I have described (1930) in /. radiotus, Topsent. For example, with increase in size the specimen tends to become flabellat
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