140 BRITISH PALAOZOIC SPONGES. 
plates, and overlap the rays of adjoining spicules. The ray pointing to the outer 
margin of the Sponge not infrequently projects over the spicular plate in advance 
of it. The entering or vertical ray of the spicule is usually contracted immediately 
beneath its junction with the transverse rays, it then expands and is nearly evenly 
cylindrical to its junction with the plate of the inner wall. The characters of the 
plates forming the inner or upper wall in this species have not clearly been made 
out. They appear to be sub-quadrate in form, and in close contact with each 
other. It is doubtful whether there were perforations at the angles of the plates, 
as is clearly the case in R. occidentalis, Salter, and in a specimen from the 
Devonian of Canada, which, in all other respects, resembles the European forms 
of this species. 
The only undoubted example of this species from British strata is a frag- 
mentary individual discovered by the late A. Champernowne, Hsq., F.G.S., showing 
an impression in hardened mudstone of a portion of the inner surface of the wall 
and transverse sections of the vertical spicular rays (Pl. IV, fig. 1). Fragmentary 
specimens likewise occur in Wenlock strata at Malvern, which may provisionally 
be referred to this species, though the characters preserved are insufficient for 
satisfactory determination. ‘They consist of impressions of the under or outer 
surface of the wall of flattened specimens of at least 120 mm. in diameter, showing 
the lozenge-shaped depressions formed by the casts of the spicular plates and 
traces of the transverse rays beneath them (PI. II, fig. 3). In none of the 
specimens is the structure clearly shown, and the principal grounds for referring 
them to R. Neptuni are the correspondence in the form and dimensions and in the 
crenulated margins of these outer plates to those of typical forms of this species 
as figured by Giimbel.’ 
Distribution.—Silurian: Wenlock strata, Malvern. Middle Devonian: Mud- 
stone Bay, Devonshire. Also in Devonian strata at Chimay, Couvin, and other 
localities in Belgium, Ober-Kunzendorf, Silesia; Hifel, Germany; near Widder, 
Ontario, Canada. 
Sub- Order.—OctactINELLID®. 
18. AsrrmosponciA Devonrensis, Hinde, sp. nov. Plate IV, figs. 8a—8 c. 
The form of the Sponge unknown; the species is based on detached spicules 
in which both the rays of the vertical axis are developed, as well as the six hori- 
zontal rays. The rays are robust, conical, circular, or slightly compressed in 
' « Beitrige Abhandl. d. k. bay. Akad. der Wiss.,’ Cl. ii, Bd. xu, pl. a, figs. 3a, 4a. 
