298 



mal wall, which is somewhat smaller in the ooecia-bearing zooecia than in the 

 others, and the bridge separating this from the secondary aperture 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 situated at the 

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

 each inner wall is provided with a smaller number of similar plates, on the 

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

 on the basal wall. The outermost 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 zocecium, others on the distal wall. These inner terminal parts 

 are sometimes bifurcated, sometimes sac-like widened, but always have two separate, 

 uniporous rosette-plates, which belong each to its own side of the separating wall 

 and these marginal rosette-plates thus form a connecting link between the com- 

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



The ooecia in conjunction with the peristome form large, mamma-like protu- 

 berances which are not sharply marked off from the zooecia and they seem usually 

 to occur on all zooecia in one or in several (up to 6) successive circles, more 

 rarely only on one or several zooecia in one circle. Whilst the single ooecia 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 ooecia-bearing branches easily recognizable. The ooecial cover, which like the 

 rest of the zocecium 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 ooecium formed by two calcareous layers, which can only be seen 

 distinctly in longitudinal sections obtained by grinding. 



The avicularia are fairly small, of a jjyriform 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 every two zooecia 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, bifurcated, cylindrical bran- 

 ches, on which the zooecia are arranged in whorls round a small, cylindrical 

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

 nel, Lat. 23" 20' N., Long. 18" 30' E., 17 fathoms depth (Andrea), 



