238 



is also developed as an aviciilariiiiii on llie adzorrcial side of the daugliter-zooe- 

 c'iuni, is very small, arched and ralher slronglj' |)rojecting. The adzo(t'rial, inlVa- 

 scapular chamber of the molher-zoa'cium is not developed. 



The ooecium. The gonozocrcium springs from a molhcr-zotrciiini and is of 

 about the length of an ordinary zoo'cium, but much broader and 3 — 4 times as 

 long as the small, cap-shaj)cd, covering kenozooecium. The slruclure of the sternal 

 area is similar to Ihat of the ordinary zoa'cia, and Ibis may also be said of the 

 lateral chambers on the adzorrcial side with exception of the first one, which is 

 smaller and more steeply ascending. On the adzooecial side of Ihe gonozoo'cium 

 the lateral chambers are much more faintly developed, silualcd almost vertically 

 on the frontal wall, and the scapular chand)er is not developed as an avicu- 

 larium. No unpaired, median pores are found, and within the two Iransver.sely 

 oval fenestra", which are heie <piilc frontal, we find but one group of spinous 

 processes and no pores. On the lo|) of liie kenozoojciiim Ihere is a rather large, 

 quadrangular or triangular chamber, compressed from front to base, which is 

 sometimes undivided, sometimes disided bj' two septa into three cavities, of which 

 the central one was not developed as an avicularium on anj' specimen I have 

 examined. 



Form of colony. The regular alternation of uni- and bi-zou'cial inleinodes is 

 broken in the terminal part of the princi[)al branches by two or three bizoo'cial 

 inlernodes succeeding each other (2, 2, 1, 2, 2, 1 ... . or 2, 2, 2, 1 ... .). 



Of tills species I have examined some fragments from Port Western. 



Besides the four, above-descril)('d species whicli show a uundier of agreeuienls 

 with Scnlicella manjarilacea, it seems, that the following tertiary species described 

 by Mac Gillivray' must be referred to this genus, viz. Cdlenicelln lincata. (jtl. 

 latijioiis and Ckiinporella lomjicollis. 



Cribricella n. g. 



The slenial area has numerous, scattered ])ores, of which the outermost are 

 disposed in a distinct curved line, and a small, transversely oval cryptocysl 

 lamina on its inner surface. The hinge-teeth are rudimentary or indistinct and 

 never jirojecting freely in Ihe a])erlnre. The occlusion lakes ])lace in a way similar 

 to that in Scnlicella. 



' 76, p. 14, 1,'), 2\. 



