Vol.58.] | THE CAMBRIAN, ETC. OF THE MALVERN HILLS. 113 
specimens, the most perfect of which (fig. 7) is an internal cast 
showing a large well-defined oblique cone, marked by very fine 
radial strie, and apparently also by indistinct traces of concentric 
lines of growth. The cone is situated on an apparently subcircular 
7 platform, from which the some- 
what overhanging apex rises 
sharply. The apex of the cone 
~ does not extend to the edge of 
the platform. The transverse 
and dorso-ventral diameters of 
the opercuium probably mea- 
sured about 1°72 and 1°65mm. 
respectively, the relative pro- 
portions being 1°40:1. The 
measurements thus agree with 
those made on the tube itself. 
The rather thick shell itself 
is seen in the counterpart of 
the specimen. _ 
The internal cast of a second 
specimen (fig. 8) is essentially 
similar in shape, but the cone is 
less sharply marked off from the 
platform. In a third specimen 
(fig. 9) the conical part of the 
shell itself is preserved, and 
shows closely-set, fine, radial 
lines, and less regular con- 
centric lines of growth. 
Occurrence: Common in 
the Grey Hollybush Sandstone 
of Raggedstone Hill (M 439, 
443), associated with Hyolithus 
malvernensis, H. priuncevus, 
Kutorgina Phillipsti,ete. Two 
specimens were also obtained 
from the débris of the Malvern 
Quartzite (M 244¢). The 
species has been, moreover, 
recorded by Dr. Callaway from 
the Hollybush Sandstone of Shropshire," and by Prof. Lapworth 
from the Lower Stockingford Shales.” 
Hyolithus fistula appears to belong to Holm’s subdivision 
‘ Teretes’ (Lower and Middle Cambrian) of the subgenus Orthotheca. 
It seems to be intermediate, to a certain extent, between Orthotheca 
corneolus, Holm, on the: one hand, and the remaining ‘ Teretes’ 
(O. Hermilini, Holm, O. teretiusculus, Linnarsson, and O. stylus, 
Holm) on the other. From the forms last mentioned it is dis- 
? Quart. Journ. Geol. Soe. vol. xxxiv (1878) p. 759. 
* Geol. Mag. 1886, p. 548. 
0.5.6.8. No. 229. T 
(x 24 diam.) 
Figs. 7-9.—Opercula of Hyolithus fistula. 
