232 DR. CARPENTER'S RESEARCHES ON THE FORAMINIFERA. 



which extend from the annular passages of each zone to the cells of the next, 

 and, in the outermost zone, to the pores d, d; another portion as displayed 

 by a vertical section e, e, in a radial direction, which lays open the colum- 

 nar cells, but passes through the intercellular partitions, in alternate zones; 

 and another portion ff, as displayed by a fracture in the course of one of 

 the zones, laying open the entrances to the cells from its inner or central 

 side. 



Figs. 2, 3. Two large recent disks from the Feejee islands, plicated towards the mar- 

 gin, but one much more so than the other, and with a projection of the 

 upper and lower edges, so as to leave a deep marginal furrow: enlarged 

 2 diam. 



Figs. 4, 5. Vertical sections of two disks, drawn under the same magnifying power, 

 showing the marked difference in the size and proportions of their parts. 

 In each disk we see the central cell, with the circumambient cell laid open 

 on either side of it ; and the cells of successive zones, with their commu- 

 nications : 30 diam. 



Fig. 6. Ideal Representation of a Disk of the Complex Type; the details of the 

 different parts made-up from actual specimens : a, central cell ; b, circum- 

 ambient cell ; c, c, concentric zones of oblong superficial cells, some of 

 them laid open ; d, d, marginal pores, forming several rows ; d", d'", cor- 

 responding pores of inner zones, once marginal, but now connecting them 

 with surrounding zones; e, e, vertical section in a radial direction, show- 

 ing the zones nearest the centre to be made up of simple columnar cells, 

 but those of the remainder of the disk to be composed of two superficial 

 layers and of an intermediate stratum ; /,/, floors of the superficial cells, 

 with an aperture at each end of every one ; g, g, annular canals, running 

 beneath these floors, with the large apertures leading to the columnar cells 

 of the intermediate stratum ; g 1 , the same canals near the other surface of 

 the disk ; g", the same canals laid open through the plane at which they 

 give off the two passages into the superficial cells ; g"', the same canals, as 

 out transversely by a vertical section ; h, passage of the horizontal section 

 through the intermediate stratum, showing the summits of its columnar 

 cells about to enter the annular canals ; i, i, i, and k, k, k, passage of the 

 horizontal section through two different planes of the intermediate stra- 

 tum, showing the connexion between the columnar cells of successive zones, 

 by oblique passages running in different directions ; /, portion immediately 

 surrounding the nucleus, formed upon the simple type, as in fig. 1. 



Fig. 7- Vertical section, taken in a radial direction, of a recent disk incompletely 

 developed on the complex type ; showing at a, a single chamber of the cavity 

 of the nucleus, the section having traversed the circumambient cell; from 

 a to b, including twenty-three zones, the disk developed upon the simple 



