PERONIDELLA RECTA. 217 
small circular apertures from *3 to *5 mm. in width, whilst in others this surface 
layer is absent or partially worn away, and then there are irregular apertures 
bounded by the fibres. The apertures leading into the cloacal tube are round or 
oval, and without definite arrangement. 
A transverse section shows that the fibres bordering the exterior and the cloacal 
tube are much thicker than those of the inner portion of the wall (Pl. XIV, fig. 3 c). 
They range from *16 to ‘8 mm. in width. The structure is similar to that of 
P. pistilliformis, but the stouter fibres have a marginal layer of filiform spicules. 
The largest ray of a three-rayed spicule is *3 mm. in length by 025 mm. in 
thickness. 
This species is fairly common, but it is rarely found perfect, the stems being 
usually in fragments. The form apparently nearest allied is Peronidella cymosa, 
Michelin, sp. (non Lamouroux) (‘Iconogr. Zoophy.,’ p. 249, pl. lviii, fig. 3a), 
but the stems are smaller and more regular in their growth. Some of the forms 
included under Peronidella clavarioides, Lamouroux, sp. (‘ Expos. méthod.,’ p. 88, 
pl. Ixxxiv, figs. 8—10), are similar in form, but their fibres are more delicate, 
and the margins of the oscules are notched by surface canals. 
Distribution.—Great Oolite. Hampton Cliffs, near Bath. The type-specimens 
are from the Walton Collection in the Woodwardian Museum, Cambridge. 
25. Prronipetua rEoTA, Hinde, sp. nov. Plate XV, figs. 1—le. 
Sponges growing either singly or in small colonies of from two to four cylin- 
drical pipe-like individuals with truncate summits, which range from 11 mm. to 
20 mm. in length, and from 4 mm. to 7 mm. in thickness. The spongites usually 
grow from a thickened base, and they have generally been attached laterally to the 
spines of Echinoderms, which have now left an impress in a deep transverse 
furrow (Pl. XV, fig. 1). The outer surface is smooth with closely arranged fibres 
forming very irregular interspaces. ‘The cloacal aperture is circular, about 1°5 mm. 
in width. The fibres,as seen in section, are from ‘07 mm. to ‘17 mm. in thickness : 
only the larger three-rayed spicules are shown with any distinctness ; their rays 
range up to ‘2 mm. in length by ‘035 mm. in thickness. 
Distribution.—Corallian. Lower Calcareous Grit. Zone of Ammonites per- 
armatus ; at Suffield, near Scarborough. (Collected by Mr. 8. Chadwick.) 
