DAVENPORT: PROCESSES CONCERNED IN ONTOGENY, 185 
club-shaped pouches as the “club-shaped gland” of the Amphioxus 
larva (K. & H., Fig. 875). 
c. Through unequal growth of the different meridians of a spheroidal 
or cylindrical wall we have produced from the spheroid an apparent 
flattening on one face, such as occurs, for example, in various cases of 
* opibolie gastrulation." In Figure 16 this process is illustrated in the 
spheroidal egg of a Heteropod. (Cf K. & IL, Figs. 66, 541, 738.) 
Fig. 15, Fia. 16. 
By an excess of growth along the meridians of one side of a cylinder 
we have produced such apparent rotations of the internal organs us 
occur in Crinoids and Endoprocta, (K. & IL, Figs. 218, 732.) 
f. Let us now consider the unequal areal growth of a part of a 
bounding layer taken so small that it may be considered as nearly a 
plane or a warped surface. We shall find that the processes taking 
place in such a part are among the commonost and most importaut 
of all oceurring in ontogeny. 
This unequal growth may result, either (2) in parts formerly lying in 
ono plane moving into different, planes ; or (3) in parts formerly lying 
in one line moving out of that lino. 
9. It has long been recognized that, when in a layer excessive growth 
takes place over a restricted arca, the result is that the excessively 
enlarged area can no longer occupy its former territory. Since its 
periphery remains relatively constant while the ineluded layer increases 
Fig. 15. Section through the planula of 7Equorea, to show the greater expanse 
at one pole than at the other, See K. & IT, Fig. 14. 
Fig. 10. Sections through young embryos of Firoloides, showing how the condi- 
tion in stage B has been derived from that of stage A by greater growth along the 
meridians on the left than on the right. See K. € M., Fig. 584. 
