410 Bower. — Studies in the Phytogeny of the Fili cates. 
Moreover, the indentations of the sinuous margin correspond to these pairs 
of sori, and the convexities to the region lying between the forks of the 
primary veins. In fact, the relations in the Hart’s Tongue are exactly 
those seen in the var. Krebsii. In both there is evidence of a suppressed 
pinnation. 
A strong support of the correctness of this view is found in many 
monstrous forms of Scolopendrinm vulgar e , and especially in those designated 
var. laciniata. These are characterized by the occurrence of many projec- 
tions from the margin, which give a laciniate outline. The position of these 
laciniae is very constantly intersoral. They thus appear in just the same 
position as those slighter convexities of the normal leaf of S colop endrium or 
of var. Krebsii. If these are true indications of a suppressed pinnation, then 
the laciniate variety of S. vulgare is a retrogression towards the pinnate 
ancestry. 
But the most interesting conditions for comparison with B. pnnctulatum y 
var. Krebsii , are found in Camptosorus ( Scolopendrinm ) rhizophyllus (L.), 
Link, and C. sibiricus , Rupr., in the various regions of the very acuminate 
leaves (see E. u. P.,i. 4, Fig. 123, c). In the narrow excurrent apex the leaf 
frequently shows parallel sori of the Blechnoid type, but more or less inter- 
rupted, though often continuous for considerable distances. In a middle 
region soral arches are found, curved outwards as in B. Krebsii (PI. XXXI, 
Fig. 28, a ). In the basal region the lamina widens out into considerable 
lobes, on which the disposition of the sori is very irregular (compare 
Mettenius, Fil. Hort. Lips., PI. V, Fig. 6). Sometimes they are paired, as 
in Scolopendrinm ; sometimes they are isolated, as in Eu-Asplenium ; some- 
times back to back, as in Diplazium. Such conditions may be very nearly 
matched sometimes in the basal regions of the pinnae of B . punctulatum , 
var. Krebsii. 
The development of the typical double sorus of Scolopendrinm follows 
the same lines as that of var. Krebsii , but with differences of minor detail 
and of proportion. It has already been studied by Burck (Indusium der 
Varens, Haarlem, 1874). In the very young state a depression of the lower 
surface is first seen (PI. XXXII, Fig. 31, a ), at the margins of which the 
indusial flaps soon appear as upgrowths with the usual segmentation. Below 
them, right and left, may be seen the procambial strands. A later stage 
(Fig. 31, b) shows that the region between these strands is clear of vascular 
tissue, and the surface rises here into a ridge between the two receptacles 
a development not seen in var t Krebsii. The two indusial flaps have mean- 
while enlarged, being mostly only a single layer in thickness, but thicker 
nearer their bases. They overlap more fully than in var. Krebsii , and very 
perfectly protect the receptacles. These are formed immediately over the 
vascular strands, but are further apart than in var. Krebsii , owing to stronger 
development of the leaf-area between them. Though indications of a basi- 
