SPONGIIDA. 435 



and four of the five agree further in being the only ones of the 

 series which present an irregular erect expansion or horizontal mass ; 

 a specimen of the erect slender type also shows this colour ; neither 

 do I find any thing peculiar in the spiculation of greenish speci- 

 mens. Two of them are the only specimens received from Port 

 MoUe, the rest are from Torres Straits. But as two flattened speci- 

 mens from the Amirante Islands, in spirit, also possess a decided 

 olivaceous green coloration, I conclude it to represent a variety, 

 uniting green colour with expanded habit of growth. Possibly the 

 colours may depend on sexual characters, or reproductive condition, 

 as noted by Keller in Ohalinula feriilis. 



The general form and surface characters resemble strongly those 

 of the species named by Mr. Carter Axos anchorata, from Bass's 

 Straits, except that this is not branched ; in this the colour is given 

 as brown ; the equianchorate appears to be a modified birotulate, 

 but the skeleton-spioule is acerate. It is perhaps referable to 

 Ohondrodadia, Wyville Thomson, although, unlike the hitherto de- 

 scribed species of that genus, it has no second form of flesh-spicule. 



68. lotrochota baculifera. 

 (Plate XXXIX. fig. M ; Plate XLII. fig./.) 



Erect, formed of ^subcylindrical lobes, terminating bluntly ; dia- 

 meter of lobes about 12 millim. Surface chiefly rough, owing to 

 the projection from it, at intervals of -5 to 1 millim., of blunt 

 meandering ridges or conical blunt processes, -5 to 1 millim. high ; 

 dermis"between eminences smooth, glabrous (in parts smooth patches 

 of some extent). Texture in spirit soft to touch, but very slightly 

 compressible and elastic ; colour very dark crimson (almost black). 



Main skeleton forming somewhat irregular and wide meshes (-4 

 to "6 millim. across) ; consisting of stout compact primary spioular 

 fibres running approximately at right angles to the surface, about 

 12 to 15 spicules broad, and of similar secondary fibres, vertical to 

 the former in general direction, often meeting them in curves, about 

 10 spicules broad. Sarcode purple, stained diffusely and also 

 coloured by the presence of very abundant dark purple cells. Der- 

 mal skeleton formed by summits of primary and by uppermost 

 secondary fibres, and by long compact tracts of cylindrical spicules 

 which traverse the intervening spaces. 



Spicules : — (1) Smooth acuate, rather suddenly curved, base well 

 rounded, tapering to a sharp point from about four diameters from 

 apex, or to blunt point from about 1| diameters from the apex; 

 size -2 by -0095 to -0127 millim. : forms the main skeleton-fibre. 

 (2) Smooth, cylindrical, straight, ends weU rounded ; size -22 to -28 

 by "0063 millim. : lies loose in dermis. (3) Birotulate, shaft slender, 

 heads about "003 millim. across ; teeth four in number, bent inwards, 

 umbrella-like ; length -016 millim. 



Hab. Port Darwin, between tide-marks ; bottom mud and rock. 



The specimen consists of an irregular horizontal mass about 40 by 



2p2 



