﻿2-0 "ENDEAVOUR" SCIENTIFIC RESULTS. 



spicules being seldom more than, or even as many as, three 

 in a cross-section of the fibre; moreover, the spicules {i.e., the 

 principal spicules) are, as already indicated in the diagnosis, 

 of notably larger size. Similar spicules in moderate number 

 also occur interstitially ; and scattered plentifully among them, 

 as in O. axmelloides, are longer and slenderer (auxiliary) styli 

 of variable size. The range in size of the auxiliary styli can be 

 determined with certainty only by measurement of those which 

 lie in the "oscula membranes" (from which principal spicules 

 are always absent), since the shorter individuals are scarcely, 

 it at all, distinguishable from the slenderer principal styli. 



Loc— Port Phillip (Austr. Mus. Coll.). 



Ophlitaspongia chalinoides. Carter. 



(Fig- 59-) 



1885. Axinella chalinoides, Carter, Ann. Mag. Nat. Hist. (5), 



xvi., 1885, p. 358. 



1886. Axinella chalinoides, var. cribrosa, Carter, Op. cit., (5), 



xviii., 1886, p. 358. 

 Sponge stipitate, ramose; branches usttally someivhat 

 compressed, about 9 mm. in lesser diameter, multiplying 

 dichotomously or sometimes polytomously, and occa- 

 sionally uniting by anastomosis. Oscula, chiefly in two 

 rows on opposite sides of the branches, usually more or 

 less concealed by an extension across them of the thin 

 dermal membrane. Skeleton composed of well-developed 

 horny fibres {60 ji in diameter), forming a s^nall- 

 meshed irregular to subrectangular reticidation. Main 

 fibres provided with a meagre core of loosely and some- 

 what plumosely arranged small (principal) styli; connect- 

 ing fibres with one or a feiv spicules uniserially arranged. 

 The terminal spicules of the main fibres project slightly 

 beyond the extremity of the fibre, hut there is no special 

 development of superficial tufts of spicules as in O. 

 axinelloides. Quasi-echinating spicules somewhat scarce. 

 Auxiliary spicules {styli) are scattered interstitially in 

 considerable number, accompanied by a few principal 

 styli; they become more abundant close beneath the 

 surface {here lying parallel with the main fibres), and in 

 the dermal membrane, where they lie horizontally. 

 Megascleres: — (i) Principal styli {rarely oxea) straight, 

 cylindrical throughout the greater part of their length, 

 and gradually tapering to a sharp point, 75 to no }i in 

 length, and, in different specimens, from 3 to 5.5 p- in 

 maximum diameter; {ii.) auxiliary styli straight or flexed, 

 cylindrical to within a short distance of the pointed end, 

 120 to igs p long, and up to 2.5 p in diameter. 



