SPONGES FROM THE ABKOLIiOS ISLANDS. 487 
cortex forms only about one-third o£ the total thickness of the tube as com- 
pared with about half in the typical form, while the spicules generally are 
slightly smaller and the rays of the large dermal triradiates somewhat 
shorter and blunter. 
Register No. and Locality. III. 4, Wooded Isle. 
10. Lelapia antiqua n. sp. (PI. 25. fig. 10 ; PI. 26. fig. 8.) 
The single specimen, which is attached by its lower end to a piece of 
calcareous debris, measures 20 mm. in height and 10 mm. in greatest 
diameter. It is erect, club-shaped, somewhat curved upon itself and slightly 
flattened in one plane. The single oval oseulum, which measures S by 2 mm., 
is nearly terminal in position and has a well-developed, collar-like peristome. 
The surface of the lower two-thirds of the spongs is smooth ; that of the 
upper third is coarsely and unevenly hispid, owing to large projecting 
brushes of long, slender oxea. Colour in spirit light yellowish grey ; 
texture firm. 
The dermal cortex is about 0'42 mm. thick, the gastral cortex about 
0'13 mm., and the chamber layer, between the two, about 1'95 mm. 
There appear to be numerous small dermal pores scattered over the surface, 
but now very difficult to recognize. Short and narrow canals lead from the 
surface into large and very irregular crypts in and beneath the dermal 
cortex, from which the rather wide inhalant canals run radially inwards. 
The canal system is typically leuconoid. The flagellate chambers, thickly 
scattered in the clear, gelatinous mesoglcea, are oval and about 0"1 mm. in 
longer diameter. The main exbalant canals open radially into the large 
central gastral cavity. 
The collared cells are apicinucleate. 
The skeleton of the dermal cortex consists of two very distinct parts : 
(1) several layers of slender-rayed, normal sagittal triradiates, arranged 
tangentially, the whole about 0-085 mm. thick ; (2) a deeper and thicker 
part, consisting of longitudinal bundles of huge oxea, the whole about 
0'34 mm. thick. The dense brushes of slender oxea that project fjoni the 
surface may also be included with the skeleton of the dermal cortex. 
The skeleton of the chamber layer consists of (1) a confused interlacement 
of huge oxea, lying in all directions ; (2) radially or subradially arranged 
fibres or bundles of tuning-fork spicules, with the unpaired rays directed 
outwards ; (3) the basal rays of subgastral sagittal triradiates. 
The skeleton of the gastral cortex consists of several layers of ulate 
triradiates lying tangentially but otherwise without definite arrangement, 
backed by the oral rays of the subgastral sagittal triradiates. 
The skeleton of the peristome is rather remarkable ; there is no fringe of 
freely projecting spicules, but a thin peristomial membrane supported by a 
dense but approximately single layer of huge oxea, which are really a 
continuation of the deeper skeleton of the dermal cortex, lined by a layer of 
