284 DR. CARPENTER'S RESEARCHES ON THE FORAMINIFERA. 



nar cells of different zones ; also showing a marked difference in the size 

 of adjacent cells: 100 diam. 



Fig. 3. Horizontal section through one of the superficial layers, showing the elon- 

 gated form of its cells, and the aperture at each end of their floor: 

 100 diam. 



Fig. 4. Nucleus and surrounding zones of the excentrically-developed disk shown in 

 Plate IX. fig. 3 ; the beak-like projections at each side of the pores open- 

 ing into the new zones (shown in fig. J) are here generally deficient: 

 100 diam. 



Fig. 5. Appearance of the thin wall covering-in the central cell of a large nucleus, 

 as seen under a high magnifying power, showing the quasi-cellular mark- 

 ings : 100 diam. 



Fig. 6. Horizontal section through the intermediate layer of a disk of complex type, 

 showing an unusual irregularity in the communications of the cells: 

 100 diam. 



Fig. 7- Radial section of a recent disk, showing the complex development on the 

 normal type ; aa, bb, upper and lower superficial layers ; c, c, c, c, interme- 

 rnediate stratum ; dd, d'd', d"d", summits of partitions between successive 

 zones, forming the floors of the superficial cells ; e, e', e", oblique passages 

 through the floors of the cells of the superficial layer, leading towards the 

 annular canals ; f, /',/",/'", annular canals of four zones, near the lower 

 surface of the disk ; gg, partitions between the adjacent cells of the same 

 zones ; hh, perforations in these, through which the columnar cells inos- 

 culate with each other: 100 diam. 



Fig. 8. Tangential section of a fossil disk of complex type, showing four columnar 

 cells, aa', bb', cc', dd', of the same zone, divided by sinuous partitions, with 

 the orifices leading into the columnar cells of the next interior zone: 

 100 diam. 



Fig. 9. Similar tangential section, showing four cells of the next interior zone, aa 1 , 

 bb', cc', dd', alternating with the preceding, and the entrance of the passages 

 of the same vertical row, alternately into one and the other of the cells on 

 the two sides of each of the sinuous vertical partitions: 100 diam. 



Fig. 10. Radial section of a fossil disk, showing the incompleteness of the separation 

 of the superficial cells from the intermediate layer, and the irregularity in 

 the arrangement of its cells, with their numerous lateral inosculations 

 (compare Plate V. fig. 7, b d) : 48 diarn. 



Fig. 1 1. Radial section of a thicker fossil disk, showing a more regular arrangement 

 of the columnar cells of the intermediate layer (still, however, with 

 numerous passages for lateral inosculation), and the complete continuity of 

 the superficial cells with these: 48 diam. 



