232 



MH. S. O. RIDLEV ON ALCTONARIA 



posterior), strongly wrinkled longitudinally in spirit, except just 

 below head, where it is wrinkled horizontally, as also are most of 

 the divisions of the axis. Head of rounded, even outlines, slightly 

 antero-posteriorly compressed, incipiently lobate. Stem giving 

 rise above to a small number of short broad lobes, which break 

 up almost directly and with very few intermediate divisions into 

 the exteriorly more or less convex terminal lobules, which are 

 almost in contact laterally, and give a racemose appearance to 

 the head; lobules at surface about 2-3 millim. in diameter. 

 Zooids crowded at one level all over the rounded end of the lobule, 

 about '6 millim. across when closed. " Projecting spicules " 

 sometimes just visible above lateral border of lobule, but not 

 rising to general level of the head ; the cortical spicules of the 

 axis are chiefly horizontally arranged in the larger divisions of 

 the axis, tending to become longitudinal towards the zooids. 



Colour in spirit dirty white, with the exception of the upper 

 part of stem, which is opaque white, and of the zooids, which 

 appear normally to be black, but to be commonly bleached by 

 spirit. 



Spicules (measurements including tubercles) : — (1) Projecting 

 spicule of external zooids, fusiform, slightly flexous, with sharp 

 inner extremity, thickly covered throughout with rather promi- 

 nent but slender, bluntly pointed, smooth tubercles; those of 

 inner end backwardly directed (towards apex of spicule) ; size 

 about TO by '09 millim. ; colourless. (2) Spicules of cortex of 

 axis below lobules fusiform, rather flexuous, fairly sharp at both 

 ends, closely covered by slender, prominent, but blunted and 

 often roughened tubercles, those of ends relatively larger and 

 commonly more or less directed towards their respective ends ; 

 size of largest about 21 by '14 millim. (3) Scantily scattered 

 in the cortex, very stout and blunted forms, similar to (2), but 

 measuring about 2'6 by \18 millim. ; colourless. (4) Spicules 

 of lower part of stem fantastically and variously branched 

 forms, apparently modifications of a cylindrical or fusiform type ; 

 short diameter of axis commonly about '07 millim. ; with broad 

 black axial band or almost entirely black. 



J I ah. King Island Bay. 



Total height of single specimen (in spirit) 3 inches, lateral 

 diamefc r <>\ bead and diameter from stalk to top, both about 3 

 inches; head, hack to front about 2 inches. The stem ends 

 below in thin ribbon-like rootlets about 1-2 millim. wide. The 



