88 A MONOGRAPH OF THE TERTIARY POLTZOA OP VICTORIA. 



formed by a sharp denticle on each side ; occasionally a, small avicularium, with 

 triangular pointed mandible, to one side of the thyrostome. 



M.C. 



The whole surface is polished and glistening, and traversed by faint raised lines. 



Haswellia, Bush. 



1. H. longirostris, McG. PL XIV., fig. 20. 



(For description see Appendix). 



2. II prodncta, n.sp. PL XIV., figs. 16-19. 



(For description see Appendix). 



Bipora, Whitelegge. 



Zoarium bilaminate and expanded, or unilaminate and orbicular or conical, the 

 zocecia resting on a cancellated base. Zocecia immersed, originating in two ways, 

 either between the marginal zooecia or intercalated among the older ; thyrostome 

 arched above, with a distinct sinus in the straight lower lip and a small pore on the 

 edge of the upper reversed, the free edge of the operculum being directed from the 

 growing edge to the apex in the conical form and to the base in the bilaminate. 

 Ocecia external globose. 



The genus Bipora was proposed by Whitelegge (Pr.L.S.N.S.W., June, 1887) 

 for, among others, the species described as Lunulites philippinensis and cancellata 

 by Busk, of the generic position of which Busk himself was very doubtful. The 

 zooacia originate in two ways, those at the edge being at first nearly tubular and 

 projecting beyond the margins of the zoarium, besides which others are developed 

 between the old zocecia in various parts. According to Whitelegge, in recent 

 specimens " the first indication of the formation of a new zocecium appears on the 

 upper surface of the zoarium as an elevated or depressed round spot bordered on 

 one side by a thin layer of epitheca. At this point the ' semilunar slit with the 

 concavity directed outwards ' (already noticed by Haswell) is formed, and by the 

 gradual extension of this slit to a circular form a piece of the calcareous lamina is 

 cut out, the resulting opening being that of the peristome, and at a short distance 

 below the true aperture is seen to be also in a fully formed condition." The 

 partially formed opening is seen in several of my fossil specimens and is distinctly 

 shewn in recent B. philippinensis and Conescharellina elegans, Waters, for 

 specimens of which I am indebted to Mr. Whitelegge. It may be doubted whether 

 the genus Conescharellina of D'Orbigny should not be adopted for our species, but 

 as its true character may admit of some doubt I think it better to take the genus 



