1908.] CAPE VERDE ISLANDS SPONGES. 779 



radiates (text-fig. 165, c). Similar spicules line the exhalent 

 canals. The lateral rays are rather stout and are slightly curved ; 

 they are somewhat longer than the basal ray, which is straight. 

 The apical ray is from one-third to one-half the length of the 

 lateral rays. The average length of the lateral rays is 0-15 mm. ; 

 the average thickness of the facial rays at their bases is 0'02 mm. 

 The apical rays are less thick at their bases and are sometimes 

 curved at their extremities. 



The large oxeote spicules are slightly spindle-shaped, are 

 slightly curved, and are from twice to three times as thick as 

 the parenchymal triradiates (text-fig. 165, d). They are com- 

 pletely buried in the parenchyma or project slightly beyond 

 the dermal surface or project much beyond. They are sharply 

 pointed at both ends. In length they vary from 1 mm. to 1'5 mm. 

 and in width from 0'08 mm. to 0"1 mm. 



Minute oxea (text-fig. 165, e) are to be found in all parts of 

 the sponge, but are most numerous in the dermal cortex, from 

 which they sometimes project beyond the surface of the sponge. 

 They are pointed at both ends and are quite or nearly straight. 

 Their average length is 0"15 mm., and their average maximum 

 thickness 0*0035 mm. They vary considerably in length but very 

 little in thickness. 



The peristome consists as usual of a network of spicules of all 

 the types which occur in other parts of the sponge. 



Colour (in alcohol) white. 



This Leucon, which I have much pleasure in naming after 

 Mr. Crossland, appears to be more nearly allied to Leucandra 

 cramhessa Haeckel, than to any other previously described species. 

 It difiers from this species, however, by the presence of the 

 minute oxea, by the larger size of the parenchymal tiiradiates — 

 these being about twice the size of those in L. crambessa — and in 

 sundry minor details of anatomy. 



Distribution. Cape Verde Islands {Crossland Collectio7i). 



Leucandra gemmipara, sp. n. (Plate XL. fig. 9 & text-fig. 166.) 



Mr. Crossland collected a considerable number of specimens of 

 this species. The sponge (Plate XL. fig. 9) is elongated and 

 somewhat flattened, and forms proliferous groups of incompletely 

 separated Leucon individuals. The individuals grow to a height 

 of 1-2 cm. and a width of 4 mm. Both external and internal 

 surfaces of the body are fairly hispid. On the larger specimens 

 the oscula have a diameter of 1'5 mm. ; all the specimens have 

 oscular fringes spicules, but on yovmg individuals it is only feebly 

 developed. The thickness of the bodj^'-wall varies very little ; it 

 is about 1 mm. or slightly less, whilst the maximum diameter of 

 the central gastral cavity is 2 mm. The canal-system is typically 

 leuconoid ; the flagellated chambers are spherical or sac-shaped 

 and are rather large, having a maximum diameter of 0*1 mm. 

 The maximum diameter of the excurrent canals is only 0-15 mm., 

 and of the incurrent canals even less. The thickness of the dermal 

 cortex is 0"12 mm., and that of the gastral cortex 0*07 mm. 



