EXPLANATION OF THE PLATES. 593 



f 



PLATE XXII. 



All the figures in this Plate refer to Carpentaria. 



Fig. 1. Portion of a group of Carpenteria? growing upon the surface of Poritcs (coral) ; 

 a part of the external wall of the uppermost specimen having been thinned- 

 away by acid, so as to show the areolation of its inner surface. Magnified 

 5 diameters. 



Figs. 2, 3, 4. Interior of the first-formed chambers of three specimens, showing their 

 Globigerine characters and arrangement ; at , a, are shown the remains of 

 the yellowish-brown spongeous substance by which those chambers were occu- 

 pied. Magnified 50 diameters. 



Fig. 5. Isolated specimen of Carpenteria on the shell of Pecten, in which the chambers 

 of the last whorl diverge so widely at the base of the cone, as to be in great 

 degree separated from each other. Magnified 5 diameters. 



Fig. 6. Portion of the external wall, showing the areolated aspect it derives from the 

 gentle convexities into which it rises between the reticulations that project 

 on its internal surface ; at a is shown the natural external surface on which 

 the foramina are regularly disposed ; at I that surface has been removed by 

 grinding, so as to bring into view the inner layer of the wall, on which the 

 foramina are seen to be deficient along the projecting ribs, but to be more 

 closely set together in the portions surrounded by these (see fig. 15). Mag- 

 nified 30 diameters. 



Fig. 7. Section of a very flat specimen, parallel to the base of its cone, but not far from 

 its apex ; showing at a the vertical funnel transversely divided, at b its com- 

 munication with the last chamber, at c its communication with the penulti- 

 mate chamber, at d, d 1 , and (Z 3 three of the complete septa dividing the prin- 

 cipal chambers, and at g and g l portions of the canal-system. In some of the 

 chambers are seen spicules resembling those of Sponges. Magnified 20 dia- 

 meters. 



Fig. 8. Portion of a specimen partially laid open by grinding away the apical portion 

 of the cone : , I, c, d, as in the last figure ; e, e\ e*, secondary septa partially 

 dividing the principal chambers, but not extending to their central portion ; 

 /'/''/ 2 ' incomplete septa projecting inwards from the external wall, but not 

 crossing the cavity of tho chamber to reach the opposite wall. Magnified 20 

 diameters. 



Fig. 9. Portion of the upper part of the specimen represented at the top of fig. 1, much 

 more enlarged, showing the reticulated arrangement of those incomplete 

 septa; the spaces included in the reticulations are in some instances covered- 

 in by a thin layer of the shelly Avail which has not been removed ; but in 

 most other cases this wall has been eaten away by the acid in the central 

 MDCCCLX. 4 i 



