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Three ovicells are present in the 'Siboga' specimens; one on 112.B. (figs 11, 12) and 

 the other two on 483. B. They are of the type characteristic of the genus, occurring on the 

 basal side of a main branch, and belonging to the region of two lateral branches, one on 

 either side of the main stem (hg. 11). The ovicell is considerably longer than broad and it is 

 marked by a distinct longitudinal carina which runs obliquely, in the direction of the longest 

 axis of the organ. From this carina its sides fall off, becoming convex and joining the branch 

 in such a way that the ovicell is sharply marked off from the neighbouring parts. The whole 

 surface, with the exception of the carina, is reticulato-punctate ; the pores being situated at the 

 bottom of fairly deep pits, one of which surrounds each pore. This ovicell is bifid distally, 

 althoueh this character is not found in the other two. On viewing the branch from the frontal 

 side (fig. 12), it is seen that the ooeciostome occurs in the proximal axil, and is visible from 

 this aspect. The tube is not developed on the side towards the axil; but on the opposite side 

 it is raised and hood-like. The ooeciopore is subtriangular, the apex of the triangle being 

 directed towards the axil. The ovicells of 483. B. are essentially similar. Both are borne by 

 one small fragment, and have their ooeciostomes in a corresponding position. The tube of the 

 ooeciostome is, however, indicated on the axillary side, and the ooeciopore is more rounded. 

 These ovicells are considerably broader proximally than distally. One of them sends a lobe 

 along the back of the proximal branch: and its carina, which is much less developed than in 

 112. B., gives off a branch, nearly at right arigles, extending along this lobe. The other ovicell 

 shows the same features in a less marked manner. 

 Measurements, in u. : 



Diameter of main branch, fig. n, 700 — 750; 



Diameter of left lateral branch, fig. 1 1 , 400 ; 



Length of ovicell, fig. 11, 1,900; 



Diameter of ovicell, at proximal end, fig. 11, 1,200; 



Length of longest peristome, without spines, fig. 10, 425; 



Length of longest suboral spine, fig. 8, 525; 



Diameter of e.xpanded part of peristome, close to orifice, fig. 12, 150. 



Diameter of ooeciopore, fig. 12, 120. 



2. Hornera caespitosa Busk. (PI. XI, fig. 13). 



Hornera caespitosa Busk, 1875, "Cat. Mar. Pol. Brit. Mus.", III, p. 17, PI. XV, figs 1 — 3. 



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



Zoarium with branches which are curved towards the frontal surface, some of them 

 showing a lateral curvature. Basal surface very convex, the ridges neither regular not prominent, 

 each bearing a series of granulations. Frontal surface not showing regular longitudinal ridges, 

 even in young branches; with pores in depressions separated by obscure curved ridges. Zooecia 

 not arranged in series, their orifices quincuncial. Most of the peristomes are not raised, but 

 the outer peristomes may be somewhat prolonged and then project at the sides of the branches. 

 Ovicells wanting. 



J 49 



