SPONGES.-HALLMANN. 



257 



by a layer of spongin ; but this Is often so thin as to be indis- 

 cernible, and in such cases the spicules sometimes appear as if 

 echinating. Quasi-echinating spicules are also of common 

 occurrence on the more superficial fibres ; these, in some if 

 not all cases, mark the starting-points of new fibres. Scattered 

 (auxiliary) subtylostyli occur interstitially, in some parts 

 sparsely, in other parts in great abundance. 



Mcgascleres. — 



(i.) Principal styli straight, usually slightly expanded at 

 the base, very nearly cylindrical throughout about 

 three-fourths of their length and tapering thence to a 

 sharp point, ranging in length from about 130 to 

 190^, and \\ith a maximum diameter of \2 }4. 



(ii.) Straight auxiliary subtylostyli or styli, 130 to 300 k 

 in length and 6 ft in maximum diameter. 



Microsclcrcs. — 



(i.) Isochelae palmatae, fairly plentiful, 10 ^ long. 



(ii.) Toxa, comparatively scarce, in shape somewhat re- 

 sembling the conventional bow of archery; length, 

 25 to 80 ^ ; diameter of the stoutest, 3 p. 



/^oc. — Coast of New South Wales, Shoalhaven Bight, 

 15-45 fms. ("Endeavour"). 



Ophlitaspongia subhispida, Carter. 



(Plate xxxvi., fig. i ; and fig. 54.) 



1885. EchinocJathria suhhispida. Carter, Ann. Mag. Nat. 

 Hist. (5), xvi., 1885, p. 356. 



Echinoclathria gracilis, Carter, Loc. cit., p. 356. 



.1896. Ophlitaspongia subhispida, Dendy, Proc. Roy. Soc. 

 \'ict. (n.s.), viii., 1896, p. 36. 



Sponge stipitate, with slender usually someivhat flattened 

 branches which multiply dichotomously or {occasionally) 

 polytomously, and extend, ■tc/f?! or without anastomosis, 

 in the same or in overlapping planes. Dermal membrane 

 absent, or, at any rate, indistinct. Oscida not visible. 

 Skeleton a regular scalariform reticulation of strongly 

 developed horny fibres; the main fibres contain a discrete 

 paucispicidar core, the transverse fibres are without con- 

 tained spicules. Principal styli are tolerably abundant 

 in the ground substances and common as echinating 



