Sponge-fauna of Madras. 161 



primary fibres are connected with one another by short 

 secondary fibres, which run from one to the other at right 

 angles, and thus give rise to an irregular, rectangularly meshed 

 network. The ends of the primary fibres project beyond the 

 surface in the form of tufts of spicules, and amongst the 

 shorter spicules composing these tufts there also project a 

 number of very long and slender spicules ; these reach a con- 

 siderable distance beyond the surface, and thereby give it its 

 characteristic hispid appearance. There is a considerable 

 amount of amber-coloured spongin present, uniting the spi- 

 cules into fibres ; but the fibres are very ill-defined and 

 irregular, the spicules in the primaries being arranged in 

 a more or less Axinellid manner. 



The spicules are of various forms, viz. : — (1) More or less 

 curved, gradually sharp-pointed, fairly stout, smooth styli, 

 averaging in size about 0'315 by O'Ol millim., but subject to 

 considerable variation, especially in diameter ; these make up 

 the chief portion of the skeleton. (2) Very long and slender, 

 very gradually sharp-pointed, slightly flexuous, smooth styli 

 (PI. XII. fig. 2 a) ; size about 0°8 by 0*007 millim. ; occm*ring 

 at the surface, projecting amongst the smaller spicules as de- 

 scribed above. (3) Spined styli, with a few stout, sharp, strongly 

 recurved spines. {Sometimes there are three or four unusually 

 large spines arranged like the teeth of a grapnel at the extreme 

 apex. There appear to be very few or no spines at the base. 

 These spicules are rather rare; they occur projecting ob- 

 liquely outwards and forwards from the primary fibres, at or 

 near the surface of the sponge. Size about 0*14 by 0*0095 

 millim. There occur also fairly numerous, long, slender 

 rhaphides, probably incompletely developed styli. 



The externa] appearance of this sponge is very charac- 

 teristic, and it appears, judging from the three specimens 

 present, to be very constant ; the best idea of it will be 

 obtained by reference to the figure. 



RaspaiUa Thurstoni^ n. sp. 

 (PI. XII. figs. 1, 1 a, 1 h.) 

 Sponge (PI. XII. fig. 1) erect, ramified dichotomously in 

 one plane, pedunculate. Branches long and rather slender, 

 tending vertically upwards, tapering slightly to rather obtuse 

 apices. Height of the larger of the two specimens present 

 190 millim., breadth about 145 millim., diameter of branches 

 about 4"5 millim. Surface granular, minutely punctate, not 

 distinctly hispid as in the preceding species. Texture hard 

 and tough. Colour (dry) pale yellowish brown ; one speci- 

 men has a reddish tinge at the base. 



