253 



which does not reach the ninrgin, gives off from its proximal i)art a l)rancli di- 

 rected distally and then hending almost reclangiilarly outwards lo join the supra- 

 scapular chamher. The two large lateral chamhers, occupying the greater part 

 of the I)asal surface of the zo(rcium and incompletely divided into two, are the 

 two infra-sca[)ular chamhers (fig. 11 d, 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, ohlong, multiporous one distally to the proximal 

 lateral ridge, hi the hi-zo(i'cial joints digs. 11 e, 1 1 f ) the hasal surface of the 

 zoa?cium has a similar structure on the lateral half corresponding with the 

 daughter-zon'cium, whereas on the lateral half corresponding with the mother- 

 zocecium we find instead of the hranched distal ridge an unhranched one situated 

 much higher uj), which together with the median ridge forms the houndary 

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

 regard lo the infra-scajjular chamher, which is also undivided in the half hclong- 

 ing to the mother-zoa'cium. A longitudinal section tlirough a Iri-zocecial joint 

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

 the mother-zod'cium join the daughter-zod-cia 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-zou'cium occupies the space which is 

 otherwise occupied J)y the scapular and the pedal chamher, and we cannot 

 therefore expect to find oilier chambers than llic supra-sca|)idar ones on the 

 mother-zooccium or on the adzooecial side of llie daughter-zod'cium. Accordingly 

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

 two small triangular cavities distallj' lo the avicularia, must be regarded as llie 

 supra-scapular chamhers. 



OcEcia have not been found. 



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

 and a bi-zocecial 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 lo lli 

 separate internodes in one bifurcation. 



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



Catenaria Savigny. 

 Catenicella Blainville, Vittaticella Maplesf. 

 Calloporella Mac Gillivr. ' 



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

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



' 7i;, p. s. 



