A MONOGRAPH OF THE TERTIARY POLYZOA OP VICTORIA. 51 



small avicularia supported on papilliforiu elevations. Ooeciuni above the aperture, 

 seniicirculai", depressed, with a thickened riiu. 



M.C.; W.P. (W.). Living. Australia and Florida. 



Caleschara, 3IcG. 



Zoarium encrusting, or erect and uni- or hilaminate. Zooecia separated by 

 distinct raised calcareous margins ; front covered by a thick epitheca, beneath 

 which the calcareous front wall is bevelled to the depressed centre ; on each side of 

 the calcareous front is a longitudinal fissure, and across the upper part a thickened 

 bar, leaving a membranous ^lortion aljove containing the thyrostonie, the operculvmi 

 of which is incomplete. Oo3cia altered and ex2)anded zooecia. 



1. C. deitticiilcda, McG. PI. VI., figs. 8, 9. 



G. deuticulata, McG. in P.Z.V. 48 ; Busk, C.P., Pt. I., p. 77 ; JIembram2)ora 

 deidiculatu, Hincks, A.M.N.H., February, 1881. 



Characters those of the genus. Lamina granular ; lateral fissures denticulate ; 

 aperture occupying rather less than one-fourth of the area. 



S.P. ; M.C. ; C.B.; W.P. A common living Australian species. 



In the fossils of course only the deeper calcareous front wall is seen. The 

 calcareous part between the fissures and the thickened cross-bar are usually worn 

 away, when the ZocBcia have a very different appearance, seeming to have a large 

 nearly elliptical aperture. In some specimens, however, these parts are Avell 

 preserved, and perfect and worn zooecia may be seen in the same fragment. 



Of the systematic position of this curious form, opinions may, as Mr. Busk 

 remarks, well be divided. Young recent zocecia have the structure of Membranipora, 

 but with age the deeper calcareous wall wuth its lateral fissures and cross-bar becomes 

 developed ; Hincks at first included it in the genus Membranipora, but subsequently 

 (A.M.N.H., July, 1887) ado])ts the genus Caleschara and places it in the Stegano- 

 porellidse. On the wdiole I consider its affinities are more with the Membraniporidae 

 in which I include the genus, although I am by no means satisfied that Hincks' 

 view may not be the correct one. 



Family Steganoporellid^. 



Zoarium expanded and crustaceous, or free and uni- or hilaminate, or erect and 

 cylindrical. Zocecia separated by thick calcareous margins, divided into two 

 chambers, an upper closed by a thick epitheca Avhich carries the ojierculum, and a 



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