130 



each lateral margin. The distal half of each lateral wall has 5—6 rosetle- 

 plates. 



Avicularia wanting on the fragment examined. They have been described and 

 figured by Hincks, but require a closer examination. 



The ooecia are rather large and not rarely of an outline describable as 

 quadrangularly rounded.- Along their proximal margin two indistinct cryptocyst 

 processes are seen, which are rather large at their starting-point but quickly 

 become very low. A little distal ly to the proximal margin of the ocecium an 

 extremely small pore is generally seen in the central line surrounded by a 

 thickened portion, and from this a number of partially coarse striae radiate. In 

 contrast to the distal wall in the ordinary zocecia the ocecia-forming distal wall 

 meets the basal wall of the zocecium in a curved line, which is sometimes on a 

 level with the top of the ocecium, sometimes somewhat lower than the latter, 

 but at all events considerably higher than the proximal margin of the ocecium. 

 Contrary to the case in the two foregoing species the whole of the distal wall is 

 transformed to an ocecium. It is accordingly convex in its entire extent and has 

 no saddle-shaped basal part with rosette-plates. 



The colonies, which are branched dichotomously, differ from those in the 

 two preceding species therein, that the separate branches do not meet. The 

 marginal pbrtion, which consists of kenozocecia, is wholh' calcified on the basal 

 side and most thickened in its outer half, for which reason the colony is seen 

 surrounded by a white margin. 



I have examined a fragment of this species from Victoria (The Zoological Mu- 

 seum of Cambridge, Dr. S. Harmer). 



Family Scrupoeellariidae. 



Cellulariidae Hincks. 

 (Pis. II and XXII). 

 The zooecia are as a rule strongly calcified, with a membranous frontal area 

 occupying a larger or smaller part of the surface. An arched gymnbcyst of larger 

 or smaller extent is found in most species proximally to the frontal area, and 

 there is usually a more or less well-developed, most often finely granular second- 

 ary cryptocyst. The margin of the aperture has as a rule 1—2 pair of spines 

 distally, while from the approximate centre of the inner margin a spine, plate- 

 like widened or branched at the end, very often arises and may cover a larger 

 or smaller part of the frontal area. The distal wall, consisting of a horizontal 

 basal and an obliquely ascending frontal part, has usually numerous, small, 

 scattered, uniporous rosette-plates basally, while the distal half of each lateral 



