237 



(e. g. in a form iVoin Twofold Bay) l)e very long and poinlcd, is, apart from a 

 number of scattered pores, wholly calcified. The infra-scapular has a small, ob- 

 long opening on the ])asal side and a smaller one on the fronlal side, and the 

 pedal chamber has most often a long, narrow frontal opening. The mother- 

 zott'cium has an extremely small, slit-like, adzou?cial, infra-scapular chamber 

 (ni. III). 



The ooecium. The gonozooeciuni, which is but half as long as the covering 

 kenozooecium, is situated on a mother-zooecium. Its sternal area is as long as the 

 aperture and provided with 4 — 5 small fenestrse and as many spines, of which 

 the two distal are much higher than the others. Each of these has a large, inner 

 cavity with generally three pores, of which two are seen just inside the oral 

 margin. The other spines are short and narrow, and the inner cavity may often 

 be wanting. The high kenozoa>cium has dislally to the aperture a longitudinal 

 belt bounded by two parallel lateral margins. This bell reaches the two lateral 

 fenestra; and has a small, oval pore proximally. Within each of (he two long 

 lateral fenestrse we see an oblong group of pores, the projecting reticulation of 

 which does not, or but to a small extent, end in spinous processes. The support- 

 ing processes springing from the owcium apjiear in great numbers over the larger 

 part of the frontal surface. On the top of the kenozoa>cium there is sometimes 

 a small, rounded, compressed, wholly calcified cavity, sometimes an avicularium, 

 which again communicates with two lateral cavities. 



Form of colony. In the principal branches the uni- and bi-zocrcial inter- 

 nodes alternate according to the formula 2, 2, 1, 2, 2, 1 ... . 



Of this species I have examined colonies from Port Phillip and from Two- 

 fold Bay. 



Costicella benecostata n. sp. 



(I'l. XII, ligs. 1 ;i, 1 I), IM. \X, lit^s. 9 a). 



The sternal area, which is about twice the length of the aperture, is [)ro\ ided 

 with 8 — 14 small, round fenestrse, and with as many hollow spines separated by 

 distinct fissures. Most of these s[)ines are rather high, (piadrangular and only the 

 two or three proximal ones are conical. The first two spines are much higher 

 than the others, but the inner cavity is often comparatively small. Further, the 

 relative position of the two rows of spines may vary considerably, as they may 

 sometimes be wholly or partly opposite, sometimes wholl)' or ])arlly alternate. 



The lateral chambers are much more calcified than in tlie other species, 

 and with exception of the supra-scapular one, which has on its basal surface 

 I wo small excisions, they have but a few pores. The scapular clKunber, which 



