BY E. F. KALLMANN. 435 



a more or less distinctly reticulate pattern; these tufts, for the 

 most part, are the outer ends of radiating spicule-strands into 

 which the outwardly running (secondary) fibres of the main 

 skeleton break up on nearing the surface. 



Spicules. — (a.) The oxea are mostly straight or nearly so, and 

 abruptly sharp-pointed (tornotiform); among them, rare indi- 

 viduals occur, which are more or less rounded off at one extremity 

 (stylote). Their maximum size in different specimens is fairly 

 constant as regards length, but variable as regards stoutness : 

 in Dendy's slide of Rhaphisia anonyma, they measure from 155 

 to 265 /x in length by at most 6 /z in diameter; in the type-speci- 

 men of Renie7'a pandcea, 165 to 245 by 8 /x; in the type-speci- 

 men of ''^Halichoitdria rubra" 160 to 230 by about 7 /x; and in 

 another specimen, of unusually cartilaginous consistency, 150 to 

 275 by 12/x. 



(6.) The raphides are straight, slightly fusiform, asymmetrical 

 with regard to opposite extremities; they taper gradually to a 

 very fine point at one extremity, are abruptly truncated and 

 produced into a minute extra-axial mucro at the other, and, at a 

 distance of between one-sixth and one-tenth their length from 

 the latter end, exhibit a small bulbous dilation. The spinules 

 are very minute, are most pronounced at the basal end of the 

 spicule, and, gradually diminishing in size, finally become indis- 

 cernible somewhere about the middle of the spicule. The spicules 

 are of two sizes, the larger being the more numerous. The 

 smaller occur plentifully in Dendy's slide of R. anonyma, but, in 

 all the other specimens examined, including the one from Port 

 Phillip, they are rather rare and in some cases apparently absent. 

 In the two Port Phillip examples, the longer raphides measure 

 from 135 to 175 /x, while in the Port Jackson examples, with 

 one exception (viz., the specimen with oxea 12/x in diameter), 

 they are shorter, having a maximum length varying between 138 

 and 150/x; their maximum stoutness varies in different speci- 

 mens, proportionately with that of the megascleres, from less 

 than 1 /x to about 2 /x. The smaller raphides are extremely 

 slender, and seldom more than 40 or 50 /x long. 



Locs. — Port Jackson and neighbourhood; Port Phil h' p. 



