450 Mr. H. J. Carter on the Fossil Foraminifera of Scinde. 



perhaps, some delicate canals of union between the chambers 

 through the interseptal spaces, too small, in my specimens, to 

 be satisfactorily seen. 



Vertical growth. — This, on the other hand, is composed of 

 columns of compressed chambers of an irregular shape (d), which 

 grow out vertically from the layers of the horizontal plane, and 

 beginning from the central cell, increase in number, vertically 

 and horizontally, with the extension of the horizontal plane, 

 which thus causes them to be most numerous in the centre, and 

 so assume a convex form, which is most prominent at this part. 

 Besides this, the difference in degree of vertical compression, in 

 these cavities, leads to the centre in one specimen being abruptly 

 raised and in another almost flat, viz. where they are inflated and 

 compressed respectively ; added to which the prominence in the 

 centre may also depend more or less on the size of the central 

 and circumambient cells. 



With the layers of compressed chambers a number of opake 

 white columns, consisting merely of condensed shell-substance, 

 are developed (d\), which, arising in points situated on the inter- 

 septal spaces of the horizontal plane, gradually increase in thick- 

 ness vertically, as they radiate also, slightly, from their origins, 

 to terminate on the surface (b 2) . 



The compressed chambers of the vertical structure, as be- 

 fore stated, are very irregular in form (a 2, a), and much 

 larger than the chambers of the central plane, from which they 

 are developed partly through the medium of minute vertical 

 tubes extended through the shell-substance of the test, in the 

 same way as in Operculina and Nummulites (d 3, g 4), and 

 partly by stolon-processes passing obliquely upwards through 

 the intercameral spaces (es, / 3, 4). Thus each compressed 

 chamber is seen to be united to those immediately above and 

 around it by several of these processes ; and thus these cavities 

 assume a columnar arrangement radiating from the central 

 plane, while part of the interspaces between them is filled up by 

 the opake columns. But the opake columns, as well as the 

 columns of chambers, bifurcate, and thus become multiplied to 

 fill up the intervals which would otherwise be caused by their 

 radiation, whereby also the chambers become diminished in size, 

 and thus, on the surface, appear subordinate in this respect to 

 the peripheral ends of the columns (a 1) ; so that the convex 

 surface of the fossil presents a number of white points, which 

 are the ends of the opake columns of shell-substance, surrounded 

 by polygonal divisions which, on their part, are the ends of 

 the columns of the compressed chambers (a), the interspaces 

 between which, again (that is, between the chambers), form 

 the radiating straight stellate lines of connexion between the 



