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



trated specimen of Orbitolites Mantelli in my possession presents 

 six at the circumference, all of which communicate in the way 

 mentioned with the outer rows of chambers (g). 



The annular system (k3, Iz), on the other hand, consists of two 

 planes only of canals, arranged in concentric circles, which are 

 situated respectively on either side of the horizontal plane, on a 

 level with the end of the chambers, with which they are in con- 

 tact on the inner side, one to each row (g 4) . Why these canals 

 should not be scolloped or wavy in the infiltrated specimens, as 

 they are in the uninfiltrated ones and in Orbitolites (PI. XVII. 

 fig. 2 0), I cannot say. 



In connexion with these, again, there are other indistinct sets 

 of more delicate canals, one of which unites the annular bands 

 transversely, that is, passing between the chambers (/4), another 

 unites them vertically {g 6), and a third set, which is only seen 

 here and there, proceeds vertically outward between the cells of 

 the vertical growth, where it appears to be lost. The first set 

 corresponds with the transverse branches between the annular 

 canals in Orbitoides dispansa and to those which, in Orbitolites, 

 appear to give origin to the chambers of the following row. 



Vertical growth. — This, again, in its mode of increase, convexity 

 of the layers of which it is composed (PI. XVI. fig. 2 b 2), con- 

 sequent compression and columnar arrangement of the cham- 

 bers (d), their being larger than the chambers of the horizontal 

 plane with which they are in contact and from which they are 

 developed, the occasional bifurcation of the columns, and the 

 successive development of the compressed cavities of which they 

 are composed being due to minute vertical tubular communica- 

 tions which pass through the shell-substance exactly like those 

 observed in Operculina and Nummulites (d 1), together with the 

 lateral stolon-processes traversing obliquely outwards the inter- 

 cellular spaces (d 3), — all exactly resemble the same parts in 

 Orbitoides dispansa. But there is a total absence of the opake 

 columnar structure; and the columns of compressed cavities, not 

 having this obstruction to their lateral development, are wider at 

 their peripheral ends, while the intercameral spaces are conse- 

 quently smaller than the same parts in Orbitoides dispansa (see 

 sections c, d). The peripheral ends of the chamber-columns are 

 also more or less circular, and in the little angular spaces between 

 them may be seen the ends of one or more of the ascending inter- 

 communicating canals which connect the columnar chambers 

 vertically, and thus complete the line of transit between the 

 centre and surface, besides affording stolons, perhaps, for the 

 formation of new chambers (c3, e*,fi). 



Hence there is a great difference between this fossil and Or- 

 bitoides dispansa, while no one can help seeing that it is most 



