253 



which does not reach the margin, gives off from its proximal part a branch di- 

 rected distally and then bending ahnost rectangularly outwards to join the supra- 

 scapular chamber. The two large lateral chambers, occupying the greater part 

 of the basal surface of the zooecium and incompletely divided into two, are the 

 two infra-scapular chambers (fig. lid, d. Ill), and each of their two parts has 

 a separate pit with pores, of which a very small one is situated near the avi- 

 cularium and a large, deep, oblong, multiporous one distally to the proximal 

 lateral ridge. In the bi-zooecial joints (figs, lie, 11 f) the basal surface of the 

 zooecium has a similar structure on the lateral half corresponding with the 

 daughter-zooecium, whereas on the lateral half corresponding with the mother- 

 zocecium we find instead of the branched distal ridge an unbranched one situated 

 much higher up, which together with the median ridge forms the boundary 

 of the undivided supra-scapular chamber. We find a similar contrast with 

 regard to the infra-scapular chamber, which is also undivided in the half belong- 

 ing to the mother-zooecium. A longitudinal section through a tri-zooecial joint 

 dividing it into a frontal and a basal half shows that the two lateral surfaces of 

 the mother-zooecium join the daughter-zooecia in the whole of their length and 

 communicate with them through two groups of uniporous rosette-plates, a distal 

 and a proximal group. Thus a daughter-zooecium occupies the space which is 

 otherwise occupied by the scapular and the pedal chamber, and we cannot 

 therefore expect to find other chambers than the supra-scapular ones on the 

 mother-zooecium or on the adzocecial side of the daughter-zooecium. Accordingly 

 the two large cavities, which we called the distal chambers, together with the 

 two small triangular cavities distally to the avicularia, must be regarded as the 

 supra-scapular chambers. 



OoBcia have not been found. 



Form of colony. The colony is composed principally of tri-zooecial internodes, 

 and a bi-zooecial internode is found only at the base of each fresh branch. It is 

 less branched than in the other species of this family and we may find up to 13 

 separate internodes in one bifurcation. 



I am indebted to Miss Jelly for a fragment of this rare species from Victoria. 



Catenaria Savigny. 

 Catenicella Blainville, Vittaticella Maplest. 

 Calloporella Mac Gillivr.^ 

 A sternal area and an inner cryptocyst lamina wanting and the frontal surface 

 only provided with extremely fine, scattered pores. The aperture, which has a 



• 76, p. 8. 



