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Zoarium saucer-shaped, attached by a thick short stem, which bifurcates repeatedly to 

 form a number of narrow branches, of nearly uniform width. The angle between two branches 

 of a bifurcation is acute. In specimens which have grown vigorously, the two branches formed 

 by a bifurcation are more or less parallel, and resemble the prongs of a tuning-fork. Branches 

 subtriquetrous in transverse section, the basal surface slightly convex and the two lateral surfaces 

 sloping upwards to meet one another in a rounded ridge which runs along the middle of the 

 frontal surface and unites the peristomes of the median zooecia. In basal view the branches 

 appear narrow and strap-like, with sharply marked, parallel, straight or slightly sinuous lateral 

 edges, each of which is formed by the outermost of a series of ridges which occur on this surface 

 of the branch. These ridges, which are usually about 6 — 8 in number, run longitudinally along 

 the basal surface. At the growing ends (fig. 8) they appear as longitudinal carinae on the basal 

 surfaces of the young zooecia. In the interzooecial grooves thus formed are the ordinary zooecial 

 pores. By the subdivision of the grooves the pores become included in a longitudinal series of 

 cancelli, each of which contains one or more of the pores. In the older parts of the branches 

 the openings of the cancelli appear as a single series of moderately large pores, corresponding 

 with each of the original interzooecial grooves, which are now .separated from one another by 

 ridges with rounded sides. A similar set of cancelli are developed on the fronto-lateral sides 

 of the branch and on the ovicells. Series of zooecia oblique, regularly alternating on the two 

 sides of the branch; 3 or 2 zooecia in each series, the innermost zooecium much the most 

 prominent, and the outermost one with its orifice not or hardly raised above the level of the 

 surface of the branch. Ovicells developed just before or at a bifurcation, commonly simple, 

 but occasionally bifurcating with the branch. The frontal surface of the ovicell is much raised 

 and is covered with conspicuous cancelli, at the bottom of which are pores of the usual type. 

 The ovicell corresponds in length with several of the oblique series of zooecia. Between each 

 two series the wall of the ovicell, on each side, is composed of a flat, thin plate which is 

 thickly covered with pores; thus forming a series of lateral porous windows, the number of 

 which corresponds with that of the intervals between the series of zooecia which are involved 

 in the ovicell. These porous windows develop no cancelli. Each ovicell has a single ooeciostome, 

 which occurs at either the proximal or the distal margin of one of the lateral windows, and 

 has the form of a convex hood overarching the window and bearing the slit-like ooeciopore 

 on its inner side. 



This very beautiful species has frequently been described and is characterised by an 

 unusual number of distinctive features. It seems to be always more or less saucer-shaped, and 

 to be attached by a central or sub-central stalk. Its branches are arranged in a single tier 

 (subject to occasional irregularities of growth) ; and from their narrow form and the acute angles 

 formed by their bifurcations, a large number of branches can be accommodatèd in the space 

 available. The tuning-fork-like mode of bifurcation (fig. 8) is very characteristic of well grown 

 colonies. The largest colony observed measures 18 mm. in greatest length; but this measurement 

 is really a radius of the colony, which may be estimated to have been something like 36 mm. 

 in diameter when complete. The specimens recorded above from Victoria are much smaller, 

 the diameter of the largest being only 7 mm., and most of them being not more than 4 or 



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