vnth an Account of some new Foraminifera. 275 



them out. They are discoidal, convex on both sides equally, 

 -^^ inch in diameter, and -^-^ inch thick in the centre. The 

 surface is very coarsely granulated, excepting a narrow out- 

 side border on each face and the edge, which parts are but 

 slightly roughened. The granulation in some specimens follows 

 irregular wavy lines from the centre of the disc towards the 

 border ; in others it is arranged somewhat spirally around the 

 centre ; more generally, however, it covers the central space 

 thickly and irregularly. Between the smooth border and the 

 granulated central part is a slight, narrow depression, which is 

 stronger in some specimens than in others. The edge is rather 

 obtuse. 



When sections and transparent slices of these little bodies are 

 examined, the whole body is seen to be coarsely crystalline ; but 

 by means of lenses of different powers and under a strong micro- 

 scope several important indications of structure may be recog- 

 nized. The horizontal sections exhibit internal spiral walls (which 

 are not, however, in the specimens I have yet manipulated, trace- 

 able to the very centre), together with short, straight, cross 

 septa, which latter are very visible in a weather-worn specimen 

 from Purton. In the vertical sections are seen, on each side of 

 the median line, the vertical tapering " columns " (originating 

 in the local difference of structure in the shell tissue), character- 

 istic of the Nummulite group, and traces of the central hori- 

 zontal row of chambers. A line of fracture traverses this series 

 of chambers, and sometimes brownish patches stain the calc-spar 

 along this line ; but the shape of these chambers is not satisfac- 

 torily shown. 



I have not yet been able to recognize the apertures of con- 

 nexion between the chambers nor the aperture of the last outer 

 chamber. 



The horizontal median line of chambers, spirally arranged, the 

 vertical " columns," and the supei-ficial granulations (which are 

 continuous with the internal " columns ") are characteristic of 

 the true Nummulite ; but unfortunately we do not know whether 

 the position of the apertures of the cells in this little fossil cor- 

 responds with that in the genus just referred to. Provisionally, 

 however, it may be regarded as a Nummulite ; and, should you 

 see no objection, it may be termed Nummulites ? liassicus. 



This form essentially differs from M. Bouvigny's NummuUna 

 Humbertina, especially in external character and in size. 



The three Stichostegian Foraminifers from Purton are Denta- 

 lince, belonging to two species. In shape one of them is some- 

 thing like D. pauper ata (D^Orbigny), and the other approaches 

 D. Lorneiana (D'Orbigny). To describe and name these fossils 

 without figures would not be advisable. 



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