10 



times below ; with elevated granular margins, and a large 

 conspicuous pore in the centre. Vibracular cells few, irregular, 

 sometimes with an avicular opening beneath, with well-defined 

 raised margin. Under surface of zoarium with undulating, 

 broad, flat, punctate costse, bifurcating, with short blunt ribs 

 intercalated, and all circumscribed by a distinct narrow raised 

 margin. These cost® seem to correspond with the width of the 

 cells, and on the edge they often correspond with the limits 

 of a marginal cell. 



Diameter, three and a half to six millimetres ; altitude, one 

 to two. 



Dredged at 71 fathoms off Cape Three Points. 



This species is distinct from S. punctata in many respects, 

 but particularly in the one pore at the mouth of the deep cell, 

 and in the margins round the flattened ribs at the side. 



Fossil Species. 



Selexaeia paevicella, Spec. nov. 



PL II., fig. 10a— 10c. 



Zoarium large, irregularly orbicular (?), very thin, depressed. 

 Zoooecia small, horseshoe shaped, the round end below ; walls 

 thick, margins raised, lamina not visible. Avicular cells 

 elongately j>yriform ; the apex above, narrow, immersed, with 

 broad inner margin, very long, nearly equalling two cells. 

 Under surface with numerous radiating depressed ribs, not 

 bifurcating, but with undulating margins ; and in the centre a 

 single row of large pores, irregular in shape, size, and distance 

 from one another. 



The cells in this species vary much in size, and the peculiar 

 vibracular cells are different in size and shape from any other 

 species. 



Locality and Horizon. — Muddy Creek Miocene beds, near 

 Hamilton. 



Selenaeia costciicsa, Spec. nov. 

 PI. II., fig. 11a— lie. 

 Zoarium small, thin, orbicular, very slightly convex, some- 

 times almost flat. Zoooecia quite concave, semicircular, the 

 upper angles often circumscribed by the neighbouring cells. 

 Surface finely granular, waxy, shining. Aperture elongately 

 semicircular, the rounded basal edge encroaching on the low 

 margin of the cell. Avicular cells about the size of the aper- 

 ture, very narrow, oblong, or triangular, with the base 

 above, the edges studded with very fine teeth. Under surface 

 with radiating, flat, granular ribs, thickly beset with irregular 



