210 BRITISH JURASSIC SPONGES. 
18. GropitsEs, sp. (b). Plate XIII, fig. 5a. 
Trifid spicules, with straight, gradually tapering shafts, and short, nearly 
horizontally extended head-rays. Shaft 1:87 mm. in length by 05 mm. in 
thickness ; the head-rays are about ‘102 mm. in length. Accompanying these are 
nearly straight, acerate spicules, 2 mm. in length by ‘08 mm. in thickness, which 
probably belong to the same species. These spicules are now replaced by calcite ; 
they occur in a limestone matrix infilling a species of Tremadictyon. 
Distribution.—Inferior Oolite. Parkinsoni-zone in the cliff at Burton 
Bradstock. (Coll. G. J. Hinde.) 
Family.— Ruaxettipa, Hinde. 
Sponges with walls of continuous, anastomosing, plate-hke laminz or 
trabeculz, composed of agglomerated globate spicules of the same character as 
those forming the crust and axis of the existing genus Placospongia, Gray. 
(‘ Proc. Zool. Soe.,’ 1867, p. 127.) 
Genus.—RHAXELLA, Hinde. 
1890. Quart. Journ. Geol. Soc., vol. xlvi, p. 59. 
Palmate, flabellate, or rarely funnel-shaped sponges; the laminated walls 
enclosing labyrinthic, intercommunicating channels and lacunz, which open at the 
surface by sub-circular or elongate apertures. 
19. Raaxeiia perForata, Hinde. Plate XIII, figs. 7, 7 a—f. 
1890. RwaxELLA PeRForATA, Hinde. Quart. Journ. Geol. Soc., vol. xlvi, p. 59, 
pl. vi. 
1891. — — Rauff. Neues Jahrb. fiir Mineralogie, &e., Bd. ii, 
p. 370. 
1891. — — Blake. Proc. Geol. Assoc., vol. xii, p. 134. 
These sponges occur as more or less weathered-out masses of irregular outlines, 
sometimes palmate or fan-shaped, at others with a deep funnel-shaped central 
cavity. All the specimens are imperfect, the largest measures 140 mm. in height 
by 80 mm. in width. The walls range up to 14 mm. in thickness, they consist of 
