298 



mal wall, which is soniewhal smaller in the on^cia-bearing zorrcia than in the 

 others, and the bridge se[)arating this From the secondary ajjcrturc is provided at 

 its distal part with two small, triangular avicularia. Each distal wall is provided 

 over its whole surface with uniporous rosette-plates, which are silualed at the 

 end of long canals owing to the thickness of tiiis wall. Each lateral wall and 

 each inner wall is provided with a smaller number of similar jjlates. on the 

 lateral walls as a rule 2 — 3, whilst there may be up to 6 irregularly scattered i)lates 

 on the basal wall. The outermosi part of each lateral wall is further perforated 

 by the inner terminal parts of a number of pore-canals, some of which end on 

 the surface of the zoo'cium, others on the distal wall. These inner terminal ])arls 

 are sometimes l)ifurcated, sometimes sac-like widened, but always have two separate, 

 uniporous roselle-[)lates, which belong each to its own side of the separating wall 

 and these marginal rosette-j)lates thus form a connecting link between the com- 

 mon lateral rosette-jjlates and those belonging to the frontal wall. 



The ocecia in conjunction with the peristome form large, mamma-like ])n)tu- 

 berances which are not sharply marked off from the zon?cia and they seem usually 

 to occur on all zoo'cia in one or in several (up to (>) successive circles, more 

 rarely only on one or several zocrcia in one circle. Whilst the single ocrcia are 

 originally separated from their neighbours by fairly distinct depressions, they gra- 

 dually fuse together almost entirely to form ring-shaped swellings, which make 

 the oo-cia-bearing branches easily recognizable. The oo'cial cover, which like the 

 rest of the zoa'cium is provided with pore-canals, is connected with the distal wall 

 of the oral tube, and through the secondary aperture can be seen the frontal wall 

 of the actual ocecium formed by two calcareous layers, which can only be seen 

 distinctly in longitudinal sections obtained by grinding. 



The avicularia are fairly small, of a pyriform outline and provided with a 

 triangular mandible. A somewhat larger avicularium, the ascending, freely pro- 

 jecting point of which is directed proximally, is situated as a rule on the boun- 

 dary between everj' two zoci'cia a little proximally to the peristomial pore, whilst 

 a smaller immersed avicularium is situated on each half of the bridge which 

 separates this pore from the secondary aperture. The two avicularia, the points 

 of which are directed towards each other, are separated medially on the bridge 

 by a faint depression and not by a tooth-like projection as in the colony exam- 

 ined by Busk. 



The colonies are richly branched with irregular, bifiircaled, cylindrical bran- 

 ches, on which the zod^cia aic arranged in whorls round a small, cyliiulrical 

 cavity, thus giving rise to inner walls. The colonies are from the Formosa Chan- 

 nel, Lai. 2'6'> 20' N., Long. 18" 30' E., 17 fathoms depth (Andrea). 



