243 



cularium of very variable size, the distal wall of which terminates in a beaked 

 hook. This avicularium may sometimes attain the size of the zocecium. The 

 supra-scapular chamber is separated frem the avicularium by a straight wall. It 

 is a compressed, roundedly triangular cavity, increasing outwards in height, which 

 is wholly calcified with exception of a narrow, oval fissure in the inner part of 

 its roof. The infra-scapular chamber is furnished with a right-angled or acute- 

 angled corner, which forms almost a right angle with the ft-ontal surface of the 

 avicularium. It is compressed, trapeziform and calcified with exception of the 

 surface forming an angle with the avicularium. On the adzooecial side of the 

 mother-zocecium proximally to the avicularium of the daughter-zocecium there is 

 a small supra-scapular chamber and on the proximal side of the lateral spine 

 we find an extremely small, rounded chamber, which must be regarded as the 

 adzooecial, infra-scapular chamber of the mother-zocecium. A pedal chamber 

 is wanting on the daughter-zocecium, but found on both sides of the mother- 

 zocecium. 



The ooecium. The gonozocecium is a mother-zocecium and differs from the 

 ordinary zooecia in wanting the two distal spines and in having a broader sinus 

 in the aperture. The ooecium is covered by the distal zocecium, which is accord- 

 ingly provided on one side with a strongly arched expansion, the surface of which 

 has a number of scattered, wart-like projecting pores. 



Form of colony. The principal branches are composed solely of bizocecial 

 internodes, in which the mother-zocecium bears a considerably larger avicularium 

 than the daughter-zocecium and appears alternately to the right and to the left. 

 A single zocecium may spring only from the daughter-zocecium. 



Of this species I have seen a few fragments from Port Phillip. 



Claviporella aurita Busk. 

 Catenicella aurita Busk, Catalogue of Marine Polyzoa, Cheilostomata, 

 pag. 8, PI. IV, figs. 1, 2, 3. 

 (PI. XX, figs. 10 a, 10 b). 

 The zooecia oval or angularly oval with very few, scattered, fine pores, and 

 with a sternal area provided with 3—5 rather small fenestrse. The aperture, the 

 sinus of which is not longer than broad, is surrounded by 4 acropetalous spines 

 of very variable size, two distal and two lateral ones, of which the two former, 

 which diverge at a right or obtuse angle, are of a robust cylindrical form and 

 may become a little longer than the aperture. The two lateral ones are consider- 

 ably smaller and never seem to be wanting. A sutural line leads from the sinus 



16* 



