with Observations on their Internal Structure. 169 



part, which is between the centre and the margin, 3-12ths of an 

 inch (figs. 7, 8). 

 Loc. Scinde. 



Obs. This closely approaches Nummulina from its size and 

 thickness; the spire and septa however are still more or less 

 visible externally, but the increased thickness of the shell ob- 

 scures their prominence, and gives the surface more smoothness 

 and uniformity. The edge is thick and angular instead of being 

 round and cord-like as in the foregoing species, and the whole 

 now closely approaches a Nummulite. 



Nummulina, D'Orbigny. 



1- N' ? Equilateral, discoidal, more or less wavy, thin, 



gradually diminishing in thickness from the centre towards the 

 margin, presenting on the surface numerous small papillae or 

 granulations, between sinuous lines running more or less irre- 

 gularly from the centre to the circumference, the latter being the 

 most evident of the two in the young shell. Internally whorls 

 more or less wavy, more or less irregular in breadth ; the widest 

 between the centre and the circumference (2-48ths inch broad) ; 

 about twenty whorls may be counted within half an inch of the 

 centre. Compressed chambers above and below the central plane. 

 Diameter of the largest specimens 2^% inch ; thickness in the 

 centre 2-12ths of an inch (figs. 9, 10). 

 Loc. Scinde. 



Obs. The great point of difiference between this and the last- 

 described species of Assilina is the presence of the compressed 

 chambers above and below the central plane in the former. The 

 whorls here therefore are evidently what are termed embracing, 

 and the centre is prominent on both sides instead of being de- 

 pressed. This Nummulite attains the largest size of any species 

 that has come under my observation. 



2. N. millecaput ? Equilateral, discoidal, more or less wavy, 

 thick, angular at the margin, presenting sinuous lines on the 

 surface in close approximation, which extend from the circum- 

 ference to the central prominence on each side, presenting a 

 series of superficial whorls in the adult animal. Internally turns 

 of the spire very numerous, more or less wavy and irregvdar in 

 breadth, the widest between the centre and the circumference 

 ] -48th of an inch broad; about forty-eight whorls may be counted 

 within half an inch of the centre ; compressed chambers above 

 and below the central plane. Diameter of the largest specimens 

 1 j% inch ; thickness in the centre 3-12ths of an inch (figs. 

 11, 12). ^ 



Loc. Egypt. 



