311 



Synopsis of the genera. 



1) The colony with hinnecia: 



2) The colonies which have the form of a hjw cone or an arched 

 disc only show a single layer of zofpcia, whilst their inner cavity is 

 occupied by numerous avicularia placed in horizontal layers; (ocecia 



may occur) Cnnescharelliiui d'Orh. 



2) The colonies are plate-like or fan-shaped, with two layers of 

 zooecia; (ooecia are not found) liipora Whilelegge. 



1) The colonies, which have no luna'cia, are plate-like, two-layered; 

 (no O(rcia) FlahelUpora d'Orh. 



Conescharellina angulopora Tenison -Woods. 



Bipora angulopora Whilelegge, Annals Nat. Hist. (5 Sen, Vol I, 1888, p. 18. 



(PI. XXIII, figs. 7 a-7 f). 



The primary aperture is elongated oval, distnlly rounded, proximally pointed 

 and here provided with two elongated, rounded, triangular hinge-teeth, which 

 bound a narrow, elongated sinus. The peristome is formed by two thick cal- 

 careous plates, distally separated and projecting straight outwards, which have a 

 fairly strongly arched outer surface and reach almost to the proximal third of 

 the ajierture. 



The operculum, which is extremely thick and of a brownish yellow colour, 

 is strongly arched in the greater part of its inner surface while the outer surface 

 has a corresponding concavity. The inner arched part which shows two small 

 muscular dots and evenly grades into a lower marginal portion ends proximally 

 in a narrow, tongue-shaped part, inserted in between the two hinge-teeth. Each 

 zocrcium is separated from the adjacent zoa'cia by four long, narrow separating 

 walls and from one of the ahove-mentioned„small, enclosed avicularian chambers 

 by a small, innermost wall. Each of the four separating walls is provided within 

 each lateral margin with a row of up to 8 small, uniporous rosette-plates. 



The avicularia, appear in two ditl'erent forms, those placed on the zoa^cia and 

 those occupying partly the flat base and partly a great inner portion of the 

 conical colony. The latter we may call the basal avicularia. The former which 

 occur in similar numl)ers to the zoa>cia and the frontal area of which has a 

 similar length as the zooecial aperture, are provided with a broad, triangular 

 mandible with its point directed as a rule obliquely distally towards the higher- 

 placed zooecial aperture in a neighbouring row and obliquely out from the surface 

 of the colony. The strong transverse bar between the opercular and the suboper- 



