44 PROF. H. H. s^^'I^'^'EETO^' axd me. a. e. TErEMAX [vol. Ixxiii, 



Passing outwards from this, the sections show ever more clearly 

 detined indications of folding mitil at section e (tig. 10, p. 43) thev 

 are distinct enough to jjermit of comparison with the second suture 

 (9 h, p. 42). Such comparison shows that, except for the flattening 

 of the features, all essential characters of the latter are to be seen. 

 If it Avere not for the enlargement of the first lateral saddle, the 

 fifth septal section (fig. 10 e) would be identical with the second 

 suture (fig. 9 &). This discrepancy is slightly rectified in the sixth 

 section (Hg. Vdf). 



Fig. 11. — Section of whorl {x6) alonrj the datum-plane of the 

 septum ivhereof sections are shown in fif/. 10, p. 43. 



[The lines parallel to the periphery show the positions of these sections. The 

 numbers 1, 2, 3, etc. correspond to the letters a, h, c, etc. in fig. 10.] 



The seventh section (10 _^) is comparable mth the seventh 

 suture (9 c) and those which follow it as far as the second whorl 

 (9f/), or even a little later. This is shown by the appearance of 

 the internal auxiliary, and of faint indications of friUing on the 

 external saddles and on the first lateral lobes. It should be noticed 

 that at this stage, so far as main folds are concerned, the tendency 

 to flattening has been reversed, and the features are now relatively 

 deeper and narrower than in development. Section 8 (fig. 10/0 ii=^ 

 comparable with the sutures in the third whorl (9 r), differences 

 being similar to those noticed in the previous section : that is to 

 say, the crimping, having just made its appearance, is (on the 

 whole) flatter than in the corresponding developmental stage. 



