120 



the corresponding part of the avicularium a little hook. In a large number of 

 avicularia the membranous covering of the frontal area is transformed into an 

 acuminated tentaculiform process and in such avicularia there is no trans- 

 verse bar. 



The ooecia are almost semiglobular, but in the greater part of their extent 

 immersed and only projecting externally as a slightly prominent pent-roof-shaped 

 portion distally to the zocecium, which portion is at the sides bordered by the 

 avicularia. This projecting portion consists of two calcareous layers, the ectozooe- 

 cium being also calcareous. 



The colony consists of somewhat short, cylindrical club-shaped segments with 

 four rows of zooecia and 3 — 4 zooecia in each row. 



Port Phillip (British Museum). 



N. tenella Lamk. 



Nellia oculata Busk, Catalogue Marine Polyzoa, Cheilostomata, pag. 18, 

 PI. LXIV, fig. 6, PI. LXV (bis), fig. 4. 



(PI. I, figs. 13 a— 13 e). 



The zooecia elongated, quadrangularly rounded, with a proximal, calcareous 

 portion, which may occasionally reach nearly one-fourth of the whole length of 

 the zocecium. The elongated, oval frontal area is surrounded by a thin projecting 

 rim, and at its posterior marginal portion there is a small secondary cryptocyst. 

 The distal part of the frontal area, which includes the operculum, is on each 

 side separated from the remaining part by a small tooth-shaped projection of 

 the lateral margin (fig. 13 c). The distal wall and the distal half of each lateral 

 wall is furnished with a single uniporous rosette-plate. 



The avicularia which appear in pairs on the proximal, calcareous part of 

 the zocecium, are rather small, and have a large part of their chamber immersed 

 in the colony, which part is apparent, funnel-like, through the lateral walls of 

 the zocecium (fig. 13 b). At their proximal part they are provided with a small 

 pit for the insertion of the radical fibre (fig. 13 e), and at their distal part some- 

 times with an oval, sometimes a pear-shaped frontal area. The mandible which 

 has a similar, variable form and is furnished with a small, beak-like hook is 

 turned away from the zocecium. 



The ooecia are immersed for the larger part of their extent and can only be seen 

 from the outside as short, pent-roof-shaped projections (fig. 13d), which on each side 

 are separated from the lateral walls of the lower zooecia by a curved suture (fig. 13 c). 

 This projecting portion consists of two calcareous layers, as the ectoooecium is 



