' SPONGES — WHITELEGGE. 511 



Megcascleres : — (1) Shoi't, straight styli, chiefly axial and scat- 

 tered in the choanosome ; size 0-3 to 0-4 by 0-025 mm. (2) Styli 

 both marginal and terminal ; size 0-6 to 0-65 by 0-02 to 0025 mm. 

 (3) Curved oxea ; size 0'35 to 045 by 0-01 to 0015 mm. 



HTGGINSIA, Higgins. 



HIGGINSIA SCABRA, sp. nov. 



(Plate xlvi., fig. 44.) 



Station 34. 



Sponge sub-flabellate, with a few flattened branches, some of 

 which are coalescent. The figured specimen is 110 mm. in 

 height and about the same in width ; the branches are from 8 

 to 12 mm. in thickness. Surface uneven and closely conulose, 

 the conuli being about 3 to 5 mm. high, and from 1 to 3 mm. 

 apart. The epidermal membrane is neatly arranged between the 

 conuli, forming a smooth coating with here and there a few cir- 

 cular pores. Oscula, either apical, marginal, or occasionally on the 

 flat surface of the sponge ; their diameter varies from 2 to 5 mm. 



Texture hard, incompressible, and somewhat brittle ; colour 

 yellowish-cream. 



Skeleton : — The primary fibres are somewhat indefinite and 

 obscured by a confused envelope of spicules ; in some places, how- 

 ever, an axial series may be distinguiyhed consisting of from six 

 to twelve closely arranged spicules ; in longitudinal section the 

 fibres present features which may be described as nodes and 

 internodes ; the latter affords a view of the spicules indicating 

 the course of the fibres, and the former exhibit dense nodes of 

 spicules, from which the secondary fibres arise ; from their origin 

 their course is upwards and outwards ; in each fibre a distinct 

 axial thread of three or more spicules can be traced ; they are 

 frequently hidden from view by numerous sub-echinating spicules 

 which terminate in radiating tufts at the surface, being most 

 evident on the apices and sides of the conuli. 



Megascleres: — oxea of two sizes — (1) generally curved and 

 tapering to acute points about three or four diameters from the 

 extremities; size 0'7 by 0024mm. 



(2) Slender, curved, and gradually tapering to acute points ; 

 size 06 by 001 mm. 



Microscleres : — microxea somewhat boomerang-shaped, with a 

 sharp bend in the middle ; they are minutely spined throughout 

 their length, and are very abundant in the epidermal membrane 

 and scattered in the intrafibrous portions of the sponge. 



