239 



Cribricella rufa Mac Gillivray. 

 Catenicella rufa M. Gillivr., Transact. Royal Soc. of Victoria 1868, 



Vol. IX, pag. 126. 

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



The zooecia are elongated, ciuadrangularly oval, and the sternal area is pro- 

 vided with numerous scattered pores, of which the outermost are not much larger 

 than those situated further in. The aperture has a proximal concave margin with 

 a small, rounded sinus centrally. 



The lateral chambers. The scapular chamber is in most zorrcia developed 

 as a generally rather small, frontally directed avicularium, which never appears 

 on the adzocecial side of the daughter-zooecium. It is usually wanting on the 

 inner side of the single zoa-cia, which occur in rows and may spring both from 

 a mother- and from a daughler-zofrcium, but in the latter case the opposite avi- 

 cularium is often large. Of the other lateral chambers we see from the frontal 

 surface only a part of the supra-sca[)ular one, which has a membranous roof 

 but a jjrojecting calcified outer wall. The long, narrow infra-scapular chamber 

 passing from the outer side of the avicularium obliquely towards the basal surface 

 bends again more or less far down the latter surface and is at its terminal 

 part almost i)arallcl with the likewise long, narrow pedal chamber, which 

 runs along the lateral margin of the zoa'cium. The mother-zooecium has a long, 

 infra-scapular, adzocecial chamber. 



The ooecium. The gonozocrcium, which is somewhat shorter than the cover- 

 ing kenozoa'cium and situated on a mother-zoa'cium, is of the same length but 

 twice the breadth of the zoa^cia, and the structure of the sternal area is similar 

 to that of the latter. Its wide aperture has a broad, but indistinctly marked sinus, 

 on the proximal side of which a short, broadly rounded, inner cryi)tocyst plate 

 is seen. Along each lateral margin we find a long, narrow, pedal chamber, bas- 

 ally to which there is a shorter, somewhat curved one, and the chanil)ers corre- 

 spond to those of the distal group. The large covering kenozooecium is on its 

 frontal surface provided with numerous, scattered, rather large jiores, and the 

 distal group of lateral chambers is generally represented on either side by an 

 oblong, mostly membranous cavity, in which we maj' distinguish between a 

 shorter and wider distal part, which can be seen from the frontal surface, and 

 a longer, more narrow, somewhat curved part, which reaches halfway down llie 

 basal surface. The projecting wider part, which is often conical, may have more 

 or less strongly calcified walls and often be provided with but a narrow, slit-like 

 opening. In a single case it was only present on one side and then communi- 



