PERONIDELLA METABRONNII. 215 
22. PERONIDELLA TENUIS, Hinde. Plate XIV, figs. 2, 2a. 
1883. PERONELLA TENUIS, Hinde. Cat. Foss. Sponges, p. 166, pl. xxxiii, figs. 2, 
2a, 2b. 
Sponges growing in bushy masses of cylindrical or subcylindrical stems from 
3 to 6 mm. in thickness. The main stems usually divide and give rise to two or 
three individuals which either grow in apposition, or slightly diverge from each 
other. The basal portion and the lower part of the stems are covered with a 
dermal layer. The summits are gently rounded, with a cloacal aperture about 1 
mm. in width. 
The skeletal fibres are slender, about ‘1 mm. in width; near the outer surface 
they are somewhat closely arranged, but more open in the interior of the sponge- 
wall. The spicular structure is very imperfectly preserved, and the fibres now 
only show a series of three- or four-rayed spicules in the axial portion, enclosed 
by a fibrous crystalline layer. 
Bushy masses of this species reach to 48 mm. in width by 35 mm. in height. 
From P. pistilliformis it is readily distinguished by the more slender character of 
the fibres and their different spicular structure. The type-specimen is in the 
British Natural History Museum. 
Distribution.—Inferior Oolite. Pea-grit series, zone of Ammonites Murchisone, 
near Cheltenham. Also in the ‘Couche a polypiers,’ at Ranville, near Caen, 
France. 
23. Peronipenta Mertasronnil, Sollas. Plate XIV, figs. 4—4/f. 
1888. Prronenta Merasronnit, Sollas. Quart. Journ. Geol. Soc., vol. xxxix, 
p. 548, pl. xxi, figs. 26, 27. 
Sponges simple, subcylindrical or obconical in form, with a thickened, 
frequently expanded, foot-like base, straight or slightly curved, the summits flat or 
oblique, and with a relatively wide cloacal aperture. The walls are somewhat thin, 
so that the specimens are now frequently collapsed. The outer surface consists 
of an irregular mesh of fibres with very unequal interspaces (Pl. XIV, fig. 4d). 
The cloacal tube is subcylindrical or funnel-shaped, its bounding wall of thickened 
fibres perforated by oval apertures about 35 mm. in width, arranged alternately 
in vertical rows (Pl. XIV, figs. 4c, 4.e). No special dermal layer is present. he 
