6i 



zooecia to which it gives rise ; and even if its internodes are to be regarded as specially modified 

 zooecia — a view which has been supported by some authors — there is no very direct evidence 

 that this is the case, beyond the fact that the body-wall and the body-cavity of the axis- 

 internodes do not difter in structure from the corresponding parts in the zooecia. It appears 

 to me that the natural view to take of these internodes is that they represent parts of the 

 colony which are not divided into zooecia, rather than that each of them is to be regarded as 

 the morphological equivalent of a single zooecium. It is characteristic of the Vesiculariidae that 

 each internode gives rise to a number of zooecia, the arrangement of which is distinctive of the 

 several eenera. 



ö 



Vesicularia J. V. Thompson. 



Vesicularia J. V. Thompson (pars), 1830, "Zool. Res.", N° IV, Mem. V, p. 97. 

 Vesicularia Farre, 1837, Phil. Trans., p. 402. 

 Vesicularia Hincks, 1880, "Hist. Brit. Mar. Pol.", p. 512. 



The genus Vesicularia was introduced by Thompson (1830), who included in it V. cuscuta, 

 V. spinosa, V. puslulosa and V. imbricata. Of these, the first was referable to Fleming's 

 earlier genus \ r alkeria. Farre, in 1837, pointed out that V. spinosa differs from V. cuscuta in 

 possessing a gizzard; and Sertularia spinosa Linn. has accordingly become the genotype of 

 Vesicularia. The other two species included in the genus by Thompson are both referable 

 to Bowerbankia. 



Vesicularia, as now understood, (cf. Hincks, 1880) includes species with ovate, deciduous, 

 distant zooecia, contracted at the base, the polypides possessing a gizzard. In this restricted 

 form it appears to include but few species. 



Busk added two species in the 'Challenger' Report: — V. papuensis from 28 fathoms, 

 off the S. coast of New Guinea, and V. trichotoma from Bass Straits. The former at least 

 is included in the 'Siboga' Collection. 



&■ 



1. Vesicularia papuensis Busk. (PI. VI, figs 1 — 4). 



Vesicularia papuensis Busk, 1S86, Challenger Rep., Pt L, p. 36, PI. VIII, figs 1 — \c. 

 Vesicularia trichotoma Busk, Do, p. t>7> PI- VIII, figs 4 — 4.0. 



307. A. Stat. 273. Anchorage off Pulu Jedan, E. coast of Aru Islands, 13 Metres; sand and shells. 



Zoarium reaching a length of 60 mm. Stem attached by a tuft of delicate rootlets, which 

 become very fine by subdivision. Main stem covered by a thick cuticle, angulated at the nodes, 

 the angulation being alternately on opposite sides. Each internode gives off two ordinary branches 

 and sometimes a third which forms rootlets only. Stem jointed immediately on the distal side of 

 the node; a similar joint occurring at the base of each branch. The branches subdivide somewhat 

 differently from the main stem, as the principal axis is not prolonged, and the branching thus 

 appears to be simply dichotomous. Zooecia very readily lost, arranged in two alternating series, 

 on one aspect of the branch. Polypide possessing a gizzard and 8 tentacles. Vestibule and 

 collar rather short. 



61 



