A MONOGRAPH OP THE TERTIARY POLTZOA OP VICTORIA. 69 



subcircular or straight below, peristome above projecting forwards. A large 

 aviculariurn extending from the trypa obliquely to one side, the point situated 

 opposite the middle of the thyrostome. 



Var. tumida. Zooecia short and broad ; trypa round both anteriorly and 

 posteriorly ; lateral elevations more prominent and nodular or mamilliform ; 

 avicularia proportionally shorter and wider, and not extending so much to the side 

 of the thyrostome. 



S.P.; M.C. ; B.ll. ; C.B. ; Belm. ; G. Var. tumida, L.B. 



Occasionally there is an additional small aviculariurn at the base of the zooecia. 

 The lateral elevations are usually smooth, but are sometimes punctured. In some 

 specimens the base of the depression for the mandibles has two sharp prolongations 

 or denticles. On the edge of the zoarium is a series of avicularia with the mandibles 

 pointing downwards. 



Waters refers this species to Microporella jissa of Hincks (A.M.N.H., Nov., 

 1880), but although the species are evidently allied, I cannot agree with him in his 

 determination. 



4. A. mucronata, McG. PI. IX., figs. 13, 14. 



E. mucronata, McG., P.Z.V., 48 ; Microporella coscinophora, var. armatas, 

 Waters, Q.J.G.S., 1881, p. 331 ; id., A.M.N.H., July, 1889 ; Eschara sulcata, Milne 

 Edwards, sur les Eschares, 43. 



Zoarium occasionally crustaceous, but mostly erect, expanded, bilaminate and 

 variously divided or lobed. Zooecia ovate, elongated, distinct ; surface usually 

 sulcate close to the margins, with small perforations in the grooves ; a deep depres- 

 sion, with a cluster of stellate pores about the middle of the zooecium ; thyrostome 

 arched above, slightly hollowed below ; an aviculariurn below the thyrostome, with 

 the long narrow triangular mandible directed straight or occasionally obliquely 

 upwards to the lower lip of the thyrostome ; frequently an additional aviculariurn 

 towards the base of the zooecium below the perforated area, and rarely another on 

 one or both sides of the thyrostome. 



S.P. ; M.C. ; Bel.; C.C. (W.) Living. Australia, 



Waters considers this form to be a variety of E. coscinophora of Beuss. In 

 recent specimens there is a considerable amount of variation in the mode of growth 

 and form of the zoarium, as well as in the size of the zooecia and the number and 

 situation of the avicularia. In T.B.S.V., 1885, I described several forms as distinct 

 species, of which, however, A. foliacea, A. latipuncta, and A. australis ought 

 probably rather to be considered as varieties of the present species. 



