142 Australian Polyzoa. 



Williamstown, Mr. Maplestone. 



Another two-celled species occurs here, identical with 

 that described and figured as Grisidia Edivardsiana, by 

 D'Orbigny.* The present species is at once distinguished by 

 the presence of two long, jointed cilia on each cell, there 

 being but one in the former. In G Edwardsiana also, the 

 cells are much more produced, and the cilia are situated 

 much further down the back of the cells. Another point of 

 distinction, though not of much value, is that the joints are 

 black in G. Ed/cvardsiana, and light brown or the same 

 colour as the cells in G. biciliata. 



Family IDMONEIDjE. 



Genus HORNERA, Lamouroux. 

 H. joliacea. 



Polyzoary reticulate, expanded, foliaceous, convoluted ; 

 branches subcylindrical ; fenestra? large, oval or quadrate ; 

 openings of cells circular, exserted, margin divided into 

 several sharp teeth ; interstices finely granular ; dorsal 

 surface sulcate and granular. 



Portland Bay ; Wilson's Promontory ; Tasmania. 



This very beautiful species forms an expanded, foliaceous 

 polyzoary flabelliform in young specimens, expanded and 

 convoluted in those of. older growth. The Jargest specimens 

 attain a height of one or two inches. The fenestras are large, 

 generally quadrate, oval, or elliptical, broader than the sub- 

 cylindrical branches. The form of the cell varies according 

 to age. In a young small flabelliform specimen, the central 

 cells have several serrations, the serratures of the lateral 

 cells are very long and sharp, more especially at the outer 

 edge which is produced. In older specimens, the serratures 

 of the cells become worn off, so that the central ones appear 

 to have the mouth scarcely if at all exserted and entire, 

 while the lateral (those projecting on the edges of the 

 fenestras) have the outer lip produced, smooth, or slightly 

 jagged. The depth of the posterior sulci and the prominence 

 of the anterior ridges, as well as the distinctness of the 

 granulations vary a good deal. 



This is possibly the species alluded to by Busk, under the 

 provisional name of E. Goiddiana, as having been brought 

 from South Australia. 



* Voyage ; Zoologie, Zoophytes, 8, t. I. 4—8. 



