349 



fig. 4) are occupied by a very large tooth. The superior jDart of 

 this tooth divides itself in numerous ramifications, which also 

 divide themselves and form the wall of the preceding chamber, 

 thus constituting a trematophore with large openings. 



From the comparison of the sections fig. 4 and fig. 2, it appears 

 that the number of the canals increases towards the middle (in 

 length) of the chambers, i.e., the chamber xiii. (fig. 4) has only 

 three canals, the middle beginning to divide ; on the median 

 section (fig. 2) the same chamber is composed of eight canals, the 

 one being nearly subdivided by an internal rib. A similar 

 division is to be seen in one of the canals of chamber x. (fig. 2) 

 by the formation of two opposite ribs, and it is therefore evident 

 that the canals of the same chamber communicate with each 

 other as in Fahidaria discolithes. 



Exterior characters (Plate XIII., figs. 5 to 8). — Plasmostra- 

 cum free, with a regular ovoidal outline in breadth, compressed 

 on the thickness, showing only two chambers, as in the true 

 BiloculiiKP. Test porcellanous, smooth, showing by transjDarency 

 the disposition of the inner canals. Aperture formed by a small 

 exhausted trematophore (fig. 8) with large perforations of various 

 forms. 



Dimensions of the figured specimen. — Length, 2mm., 7 ; 

 breadth, 2mm., 8 ; thickness, 1mm., 2. 



Locality. — The specimens which form the subject of the present 

 note were found by Mr. Howchin in the Upper Division of the 

 Muddy Creek Beds, Victoria, which I am informed Prof. R. 

 Tate, of Adelaide, has referred to an age approximating to the 

 Upper Eocene, or perhaps somewhat later. 



Observation. — It is known that the chambers of Fahularia 

 discolithes, Defrance, are composed of several rows of longitudi- 

 nal canals of various dimensions, that the interior of the test is 

 marked by numerous pits, and that the plasmostracum is com- 

 pressed on the breadth whilst Fahularia Uowchini has a smooth 

 test, a single row of canals, and the compression of the plasmo- 

 stracum is on the thickness. 



DESCRIPTION OF PLATE XIII., figs. 5 to 8. 



Fig. 5. Fahularia HouKhin^^'^c^A^xm\.:>Qxg|&x. Lateral view of test. xlTdiam. 

 Fig. 6. " " Peripheral aspect of same specimen. 



Fig. 7. " " End view showing aperture. 



Fig. 8. " " Greatly enlarged view of aperture, exhibiting 



its cribriform character, x 40 diam. 



