1 27 



ripple-like lines of growth. In the absence of ovicells it is hardly possible to say what they 

 are; and I think it not improbable that they may belong to some other species. 

 414. B. is a fragment which may belong to the present species. 



Measurements, in >j. : 



Width of right hand branch, fig. 4, 400 ; 



Breadth of the longest series of zooecia, fig. 5, 600 ; 



Greatest length of the ovicell in fig. 5, measured in a straight line, (to end of left lobe) 2,800; 



Diameter of zooecia, fig. 5, 100 ; 



Diameter of orifices, fig. 5, up to 100. 



2 a. Tubulipora atlantica (Forbes, MSS.) Johnst., var. Jïcxitosa Pourt. (PI. X, figs 1 — 3). 



Idmonea flexuosa Pourtales, 1867, "Contr. Fauna Gulf Stream", Buil. Mus. Harvard, I, p. 1 1 1 



(off Havana, 270 fathoms). 

 Idmonea flexuosa Smitt, 1872, "Flor. Bry.", I, K. Svensk. Handl., X, N" 11, p. 6, PI. II, figs 7, 8. 

 Idmonea atlantica, var. tennis Busk, 1875, "Cat. Mar. Pol. Brit. Mus.", III, p. 11, PI. IX 



(Cf. Busk, 1886). 

 Idmonea atlantica, var. tennis Busk, 1886, Challenger Rep., L, p. 10. 

 Idmonea atlantica, var. tennis Hincks, 1880, "Fust. Brit. Mar. Pol.", p. 452. 

 Idmonea atlantica, var. tennis MacGillivray, 1887, "Descr. New. Pol.", XII, Trans. Proc. R. 



Soc. Vict., XXIII, p. 181. 

 Idmonea tenclla Ortmann, 1889, "Jap. Bry.", Arch. f. Naturg., Jahrg. LVI, Bd I, p. 59, PI. III, 



figs ia, 2,l>. 



. ' } Stat. 105. 6°8'N., 121 19' E., 275 Metres; coral-bottom. 

 477. A. ) 



iii.D. Stat. 156. o°29'.2S., I30°5'.3E., 469 Metres; coarse sand and broken shells. 



Zoarium delicate, the branches diverging, sometimes of considerable length before 

 bifurcating. Basal surface narrow, without sharply marked edges, the longitudinal septal lines 

 very distinct, but without transverse ridges. Branches sub-triangular in transverse section, the 

 median zooecia the most prominent. Zooecial series usually with two zooecia, of which the 

 median one is the longer, often considerably longer than the other. The zooecia may be 

 completely connate, but both may develop a free peristome. Ovicells short, dilating gradually 

 from their narrow pro.ximal portion, then becoming considerably inflated, but without ridges on 

 the frontal surface. Ooeciostomes ? 



The longest fragment (iii.D.) is only 15 mm. in length. This specimen and 80. A. 



have branches which reach a length of about S mm. before bifurcating, but the unbranched 



regions of 477. A. are shorter. The whole colony is very delicate, and the branches are narrow 



and without sharp edges separating the basal from the lateral surfaces. The basal surface is 



somewhat convex, and it appears to be characteristic of this form that the longitudinal septal 



lines are here very distinct, and that the "back" is smooth and without ridges. The lateral 



surfaces slope fairly steeply to the middle of the frontal surface. The series are bi-zooecial in 



most cases, though three zooecia occur rarely. The median zooecium is usually distinctly longer 



than the outer one. 



127 



