Netu or Little-knotvn Polyzoa. 359 



The groat distiuj^aiishinp: feature of this species is the enormous 

 ovoid avicularian cells, which are sometimes " twinned." They 

 cover nearly the whole surface, only a small y)Oi-tion of which can 

 be seen, not sufficient to allow of the dctoniiination of the form. 

 The distal basal margins of the avicularian cells overhang, and 

 partially hide the proximal margins of some of the thyrostomes. 



Dimorphocella portmarina, n. sp. (PI. XXVTTL, Fig. 5). 



Zoarium erect, ttabellate, bilaminate, zooecia of two forms, subtle 

 and angular, elongated; margins raised; surface granular; a row 

 of pores round the margins. Thyrostome of smaller zooecia trans- 

 versely sub-elliptical, with distal margins more curved than the 

 proximal. Thyrostome of larger zooecia transversely elongated, 

 proximal margin sometimes slightly incurved; an ovoid avicu- 

 larium, with an acute triangular mandible, in the centre of the 

 frontal wall in both kinds. The larger zooecia are more or less 

 covered with mammillated nodules. Smaller zooecia 0.4 to 0.5 mm. 

 long; 0.2 to 0..3 mm. wide. Larger zooecia 0.6 to 0.8 mm. long; 

 0.4 to 0.5 mm. wide. 



Locality . — Portsea . 



A single specimen, about 12 mm. in diameter. This species be- 

 longs to the genus DimorphoceUa, which I, in Proc. Roy. Soc, Vict.. 

 Vol. XVI. n.s. Pt. 1. p. 340, established to include D. pi/riformis 

 and D. triton, McG. sp., found in our tertiary deposits. 



The larger zooecia are present, either singly or in groups, upon 

 both surfaces of the zoarium. All the^ zooecia are somewhat irre- 

 gular in shape; in the smaller form tlie marginal row of pores is 

 very regular, but in the larger form they are sometimes obscured 

 by the mammillated nodules. The oval avicularium is constantly 

 present in both forms, and in the portion illustrated one of them 

 is reversed; the mandible pointing proximally instead of distally 



The following is a description of a very interesting form, from 

 Disaster Bay, N.S.W., given to me by Mr. C. J. Gabriel. 



Selenariopsis, n. gen. 

 Zoarium dome-shaped. Zooecia quadrate in a single layer, and 

 in radial series. Ooecia and avicularia present. No vibracula. 



Selenariopsis gabr'lell, n. sp. (PI. XXVTIL, Figs, 6, 7, 8, 9, 10). 



Zoarium a hemispherical dome, 5 mm. in diameter, 2.5 mm. hig:h. 



Zooecia radially arranged in straight rows, quadrate or sub-quad- 



