138 MR. 0. W. ANHRKWS AND OTHERS ON THE [Feb. 20, 



Skeleton consisting of slender vertical main lines, loosely joined 

 by single spicules in horizontal plane excepting near the surface, 

 where the main fibres are isolated. 



Spicules. Styles 132 xl/i, with a sharp bend at the centre. 



Oxea 144 x4ju, sharply curved at the centre, and gradually 

 diminishing to sharp points. 



The skeleton is like that of a Petrosia, but very loosely arranged. 



The specimen is too fragmentary to serve as the type of a new 

 species. 



Rhizochalina pellucida Eidley. 



1884. Rhizochalina pellucida Ridley (11. p. 608, pi. liv. tig. j). 



There are only three small fragments of fistules, the longest 

 being 4 mm. in length and 1*5 mm. in diameter. 



The spicules are slightly smaller than in the type specimen, 

 being 240 x 9 /j. in the former, and 2(30 X 10 p in the latter, but the 

 shape is the same. 



Distribution. Providence Island, Mascareue Group ; Christmas 

 Island. 



Rhizochalina sessilis, sp. n. (Plate XII. fig. 5 ; Plate XIII. 

 fig. 8.) 



Sponge pyramidal or digitate, sessile, arising from an in- 

 crusting base ; surface smooth ; consistence firm but rather 

 brittle ; colour (in formol) white-crystalline ; translucent. 



Skeleton consisting of an axial or central open spiculo-fibrous 

 network formed of broad loose strands about 10 spicules thick, 

 surrounded by a cortical network of more slender strands at right 

 angles to the central network, and of a dermal isodictval network 

 with strands 2-3 spicules thick, with unispiculate strands in the 

 interstices. 



Spicules. Oxea 372 y 14ju, curved at the centre and diminishing 

 suddenly near the ends to sharp points. Mic: oscleres 0. 



There are several specimens and fragments, most of them being 

 of flattened digitate form, the largest being 30 mm. in height, 

 8 mm. in breadth, and 3 mm. in thickness. The specimens pre- 

 served in alcohol are dark yellow at the surface, and bright yellow 

 in the interior, the formol specimens being white. 



The new species is very near Pellina eusiphonia Ridley 

 (11. p. 414, pi. xli. fig. as), from Port Darwin, but differs in the 

 shape of the sponge and in the size of the spicules. These two 

 species come within the subfamily Phlceodyctiinae rather than 

 within the Renierinse. 



Reniera innomtnata, sp. n. (Plate XII. figs. (>, (5 a ; 

 Plate XIII. figs. 5 «-/,.) 



Sponge incrusting ; colour pale brown with a faint reddish tinge ; 

 texture soft and elastic. 



Skeleton forming a rather regular reticulum of unispiculate 

 fibres with triangular (mostly) and quadrangular meshes with 

 nodes cemented with spongin. 



