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



the vertical tubuli ; 3, tubes of intercommunication between the 

 chambers of the same layer; 4, truncated ends of ditto ascending 

 to the chambers of the next lajer, or terminating on the surface 

 if there be no other layer above them ; 5, intercameral shell- 

 substance. 



/. Vertical section of columns of chambers to show the tubes 

 of intercommunication between the chambers passing up in a 

 zigzag form to reach the surface : 1, columns of chambers ; 

 2, vertical tubuli ; 3, tubes of intercommunication between the 

 columnar chambers ; 4, ditto terminating by open mouths on the 

 surface. 



f/, h, i. Vertical sections of different parts of the horizontal 

 chamber-layer, to show the various forms of the chambers at 

 these parts respectively. 



ff. Portion near the circumference, showing — 1, chambers of 

 the horizontal layer elongated vertically ; 2, chambers of the co- 

 lumnar structure ; 3, vertical tubuli of the test uniting them ; 

 4, truncated ends of the annular canals ; 5, truncated ends of the 

 oblique canals in union with the chambers of the horizontal 

 layer ; each chamber has six iraiting with it, viz. three on each 

 side, passing in opposite directions; 6, vertical canals which 

 unite the annular canals above and below the horizontal layer. 



h. Form of central chambers ; h', ditto, a little further from the 

 centre. 



i. Form of chambers of the external rows. 



k. Horizontal section of portion of the horizontal chamber- 

 layer, showing — 1, chambers; 2, oblique canals of the upper 

 layer ; 3, annular canals. 



/. More magnified view of a portion of the same, showing — 



1, chambers ; 2, oblique canals ; 3, annular canals ; 4, transverse 

 canals uniting the annular ones. 



N.B. All the figures of this Plate, with the exception of 1 and 



2, are diagrams. 



Plate XVII. 



Fig. 1. Orbitoides dispansa: m, central portion of horizontal plane or 

 chamber-layer magnified to show the cyclical growth of the rows: 

 1, central or germ-, and 2, circumambient cells, very small, the 

 latter about l-GliOth of an inch in diameter (septal divisions of the 

 chambers omitted ; intervals between the dotted lines showing the 

 "rows") ; n, ditto, ditto, with the central ( 1 ) and circumambient 

 (2) cells, very large ; the former s))herical, the latter almost ob- 

 long. Septal divisions of chambers inserted. 



0. Some of the central chambers of the horizontJil plane and 

 columnar chambers charged with propagative spherules. Propa- 

 gative spherule 1-3000 to 1 -2000th of an inch in diameter. 



Fiff. 2. Orbitolites Mantelli : m, central portion of the horizontal plane or 

 chamber-layer magnified, to show the cyclical growth of the rows : 

 1, central or germ-, and, 2, circumambient cells, very large. 

 Chambers omitted ; intervals between the dotted lines showing 

 the " rows ;" n, ditto, ditto, showing the engine-turned arrange- 

 ment of the rows at the commencement. Central and circum- 

 ambient cells very small, the largest not more than 1 -4000th of 

 an inch in diameter. Chambers inserted. 



0. Fragment of horizontal chamber-layer, to show how an 



