118 PROF, GROOM ON THE CAMBRIAN AND [Feb. 1902, 
cast, having a length of 12 mm., and a breadth of 6°5 mm. towards 
the mouth and of 4 mm. towards the apex, the relative proportion 
of depth to breadth is 1 : 2 at the larger, and 1: 1°8 at the smaller 
end, and the angle of divergence is 11°. 
In a second internal cast, 12°5 mm. in length (fig. 24), the 
breadths towards the mouth and apex respectively are 4 and 2mm., 
and the angle of divergence 12°. 
A third internal cast, with the same angle of taper, gives a length 
of 5°5 mm., and a breadth of 3 mm. towards the mouth. 
Any markings originally present are not preserved on external . 
casts of specimens from the Malvern Quartzite, several of which 
were obtained. The maximum length of this species was evidently 
not less than 3 cm., or 1 inches. 
The species probably belongs, either to Holm’s section ‘ Dorsi- 
lineati’ of the subgenus Hyolithus, or to the ‘Complanati’ im the 
subgenus Or thotheca, among which it seems to present considerable 
rese cmnlenee to O. communis, Billings, of the Lower Cambrian. 
The very flat dorsal side, the well-rounded angles, the uniform taper 
of 11° or 12°, and the size, together seem to define the species. 
Hyotiruus (?) sp. ¢. 
A fragment of a large species, apparently of Hyolithus. Length 
preserved, 11 mm.; breadth towards 
Fig. 25.—Hy anna ) the mouth, not less than 6 mm. Sec- 
sp. d. (X 4 , diam. ) tion elongated, lenticular (crushed) ; 
<a ty> lateral angles rounded. Surface ex- 
: posed (apparently dorsal) gently arched, 
showing transverse striations of growth, 
which follow the slightly curved oral 
margin, part of which is preserved. 
Obtained from the grey Holly- 
bush Sandstone of Raggedstone Hill 
(M443). 7 
Hyouiruus (?) sp. d. (Fig. 29.) 
Represented by a’ single internal 
cast. Length seen, 17 mm.; breadth 
towards the mouth, not less than 
eee ae | 4t4mm. The surface exposed (dorsal ?) 
eee is marked by a broad longitudinal 
haa ridge, which is apparently median, 
Ces and is marked by one prominent 
te] raised line, and by traces of others. 
One lateral margin, apparently com- 
eo plete, is convex, and shows a rounded 
angle. 
ez 
[From the gr ae -grey Holly- 
bush Sandstone of Ragged- 
stone Hill (M 443). ] 
