SONNINIA CRASSISPINATA. 425 



Sonninia multispinata, 8. Buckman. Plate CIII, fig. 3. 

 See Plate L, figs. 11 — 13, and page 317. 



So far as external ornaments and proportion are concerned, this is, biologically, 

 the earliest form of the Concavum-zone Sonninise. Its septa, however, are abnormal. 

 One side (a) has the outer interlobular cell of L shallower than the inner one, a 

 character of the biologically lower Zucheria (see PI. CIII, figs. 1, 2), the 

 other side (b) has the outer interlobular cell deeper than the inner. 1 In the former 

 case the terminal lobule is ultra-axial, in the latter intra-axial. In both cases it 

 is anisosceloid, but on side a, it is ecto-brachysceles, on side b it is endo- 

 brachysceles. 



The septal details do not give any authority for the present position of the 

 species. It might be placed at the head of many of the other stocks. This seems, 

 however, the most convenient place. 



Sonninia ckassispinata, 8. Buckman. Plate XCIII, fig. 7. 



1892. Sonninia crassispinata. This Monograph, Plates lvii, lxv, fig. 5 only 



(not Plate xlviii, figs. 16, 17, Plate lxv, 

 figs. 3, 4, see Sonn. reclinans ; not Plate 1, 

 figs. 16 — 22, see Sonn.locuples 2 ), p. 317. 



At p. 318 Sonn. crassispinata was divided into three varieties, a, |3, -y ; and it was 

 pointed out that they differed in external ornament and in proportion. It has since 

 been found that a and -y differ from the type in septation, that one of them is the 

 young of a form which is very different from crassispinata when adult, and that it is 

 advisable to remove the other (see p. 421). As Sonn. crassispinata there remains, 

 then, the form called /3, and it is illustrated in PI. LVII ; its whorl-section PI. LXV, 

 fig. 5. Its septa have been redrawn in PI. XCIII, fig. 7, for comparison with the 

 septa of 8o?m. locuples. It will be seen that the terminal lobule of L is intra- 

 axial and inequicellate, though practically isosceloid. 



1 The letters a and b have been inadvertently omitted in the printing of the plate. The right- 

 hand side of the keel-line in fig. 3 of Plate CIII should be marked a, the left hand b. 



2 It is requested that the explanation of the plates be altered in accordance. 



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