ON THE DEVELOPMENT OF TUBULIPORA. 91 



Millepora liliacea, Pallas (33, p. 248). 



Miilepora tubulosa, Ell. and Sol. (10, p. 136). 



Millepora tubulosa and M. liliacea, Liun. Gmel. (28, p. 3790). 



Tubipora serpens, Dalyell (6, p. 85, pi. xviii, figs. 11 — 15). 



Tubulipora serpens, Johnst. (19, pi. xxxi, figs. 4 — 6; and 20, pi. xlvii, 

 figs. 4—6). Couch (5, pp. 105 [part], 106). Smitt (40, pp. 399, 444, 

 [part], pi. iii, figs. 4« — 4c, 5a, 5b; pi. ix, figs. 1, 2a, 2b). Busk (2, 

 pp. 25, 26 [part], pi. xxii, figs. 1 — 3). 



Idmonea serpens, Hincks (18, p. 453, pi. ixi, figs. 2, 3). Levinsen (26, 

 p. 76, pi. vii, figs. 6 — 10). 



Zoarium adnate or erect, its form being greatly influenced by the sub- 

 stance on which it is growing ; commonly dividing several times dichoto- 

 mously. Zocecia curved for the most part in one plane, with the serially 

 connate, alternate arrangement strongly marked, though sometimes obscured 

 in small or irregular colonies. In well-branched colonies the inner zocecia are 

 much longer than the outer ones, so that the height of the transverse series 

 diminishes greatly in passing from the inner to the outer side. Ectocyst 

 usually vitreous and hyaline. Ooeciostome about 260 n in diameter, slightly 

 larger than the orifice of a zocecium, opening horizontally. 



Common on Hydroids (especially Hydrallmania falcata), from 20 to 40 

 fathoms ; but also found on Cellaria from the same depth, and on red sea- 

 weeds from shallower water. 



This is the " small purple Eschara " of Ellis, and the 

 Tubulipora or Id raouea serpens of most writers. I have 

 explained on p. 86 the reasons for rejecting the familiar 

 specific name. 



The distinctive feature of this species is the form of the 

 ooeciostome (figs. 7 and 8). In size it is intermediate between 

 the corresponding structure of T. plumosa and that of T. 

 phalangea^ and is somewhat larger than the orifice of an 

 ordinary zooecium. The difference between the ooeciostome of 

 T. liliacea and that of T. phalangea (figs. 5 and 6) is not 

 always apparent at first sight, the ooeciopore being often con- 

 cealed in both cases. But whereas in the latter species it is 

 seldom possible to see the ooeciopore in any position in which 

 the uninjured colony may be placed, it is nearly always 



