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



Plate 67, 

 DICTYOPORA WILSONI (P. McGil.). 



Description. — Polyzoary thin, fan-shaped, somewhat contorted, simple or 

 proliferous j fenestrse variable in size, circular or elliptical, the marginal rim nearly 

 plain and not divided into nodules j cells broad and more or less rounded above, 

 much attenuated below ; surface obscurely pitted and raised on each side of the 

 avicularian pore (frequently more so on one side) and towards the sides of the 

 mouth ; mouth circular or nearly so ; about the middle of the cell there is a round 

 pore with a small avicularium (frequently absent) with the triangular mandible 

 directed obliquely upwards. 



Reference.— P. H. MacGillivray, Tr. Roy. Soc. Vict., 1881. 



Port Phillip Heads, Mr. J. B. Wilson. 



I have only seen one specimen of this species. It consists of a 

 tuft of four separate plates, the stems arising from the same basis. 

 The plates are thin, fan-shaped, somewhat contorted, about 4 

 inches high and the broadest about the same width. The separate 

 flexible stems are up to 1 inch long, and from J to a \ inch wide. 

 To one of the plates there is a secondary plate attached at an acute 

 angle, and in another there are several plates so arranged as to 

 form two compartments, one very small, the other 2 inches deep, 

 \ inch wide in one direction and \\ in the other at the orifice. 

 In all, slightly raised ridges extend, dividing from the stem to a 

 variable distance up the plate. The fenestra are from 1 to 3 mm 

 wide, the intervening spaces, about 4 mm. The cells resemble those 

 of Kirchenpauer's Adeona arborescens, which I have not seen. That 

 species, however, seems to be sufficiently distinguished by the 

 thick, prominent ridges or ribs which extend regularly for a long 

 distance on the plate, while in D. Wilsoni they are short and very 

 slightly elevated. 



Explanation of Figures. 



Plate 67. — Fig. 1, specimen, natural size. Fig. la, margin of fenestra, with contiguous 

 cells, magnified. Fig. 16, three cells, more highly magnified. Fig. 1c, group of cells incinerated. 



The figured specimens of Dictyopora were presented by 

 Mr. J. Bracebridge Wilson ; for the description I am indebted 

 to Mr. MacGillivray. 



Fkederick McCoy. 

 [27 ] 



