288 



region and usnally in very small number on the median region The primary 

 aperlurc, whicli is provided in each corner with a strong, rounded liinge-tooth 

 (fig. 5 b), is more than twice i.s broad as it is high, with an angularly arch- 

 shaped anter and a faintly concave poster. The operculum well-chitinizcd with 

 a short muscular ridge in each corner (lig. 5 c). The secondary aperture is sur- 

 rounded by a prominent rim and lies at some distance from the distal margin 

 of the zooecium, often immediately proximally to the distal two-thirds of the 

 zoa>cium; it is broad, transversely oval. The area of ascopores is situated in a 

 depression and lies more or less far back in the proximal half of the zoa-- 

 cium; it is usually small being contained as a rule two or three times in the 

 secondary aperture. It is divided by a separating ridge into 8—6 partitions and 

 the margin of each of the.se is provided with a number of extremely thin denticles, 

 which usually reach in to the middle of the .section without however meeting. 



The gonozooecia, which are scattered sparingly over the surface of the colony, 

 partly singly, partly in groups of 2 — 8, are more than twice as large as the zooe- 

 cia, from which they also differ, in addition to a richer development of pores and 

 avicularia and a much more arched surface, by the possession of a much larger 

 ascopore-area, which shows 16—20 small partitions, and by having a much broader 

 and relatively lower aperture, the proximal rim of which is very convex. 



The avicularia, which are provided with a fairly elongated, triangular man- 

 dible, occur both independently and dependently, the former of which have a similar 

 form and size as most of the zomcia, being very sparingly scattered over the sur- 

 face of the colony. On the ordinary zoa-cia there are as a rule three, very often 

 four and sometimes five avicularia. The most constant of these is situated dis- 

 tally to the ascopore-area and its point is directed towards the aperture. One is 

 usually placed on each side proximally to or at the side of the aperture and 

 its point is usually directed in towards the middle line of the zooecium, but its 

 direction varies. One may occur in the distal part of the zocrcium and its point 

 is usually directed towards the aperture and it seldom appears on the |)roxi- 

 mal part of the zooecium. In addition to the avicularia corresponding to the 

 above, 12 may al.so appear on each side of the gonozocccium opposite the 

 ascopore-area. 



Of this species I have examined a fragment from Fort Western, Victoria (Miss 

 Jelly), consisting of a two-layered folded plate. 



