Zoology.-] NATURAL HISTORY OF VICTORIA. [Polt/zoa. 



Williamstown ; Queenscliffe ; Portland, Mr. Maplestone. 



This beautiful species forms small masses up to f inch in 

 diameter. It is fixed to narrow algse and other zoophytes l)y a 

 small calcareous attachment usually encircling the stem. There 

 are generally several primary branches which at once divide 

 dichotomously and more or less horizontally, the bifurcations 

 being repeated three or four times. The divisions of each 

 primary branch are arranged in a fan-shape, and in fine 

 specimens the whole polyzoary assumes a nearly circular outline. 

 The branches are much narrowed in front, the proximal parts of 

 the cells forming a prominent ridge. The number of cells in a 

 series varies from 1 to 4. When more than one, the inner is very 

 much longer, and when viewed in front may obscure the others (as 

 in the figure). The mouth, in perfect specimens, is usually bilabiate. 

 The back of the branches is deeply sulcate longitudinally, the 

 spaces between the sulci forming continuous, rounded, smooth 

 ridges. In the sulci there is a single series of roundish or oval 

 foramina, placed at short distances and regular intervals. The 

 ovicells are situated on the front of a branch immediately below a 

 bifurcation. They are very large, embracing the cells of 4 or 5 

 series on each side, project forwards, and are traversed by 

 reticulating slightly elevated ridges, the surface between which is 

 deeply pitted. 



Explanation of Figures. 



Plate 68. — Fig. 3, specimen, natural size. Fig. 3a, front of portion magnified, showing also 

 two ovicells. Fig. 3b, portion of back, magnified. 



Mr. MacGillivray has presented all the type specimens figured 

 on this plate, and the descriptions for the Museum and this work. 



Frederick McCoy 



[ 31 ] 



