﻿"ENDEAVOUE" SCIENTIFIC EESULTS. 



Fig. 25- P. craticia. 

 a Stylus (of the fibres). 

 b Stylus (of the cortex, 

 drawn to a larger scale 

 than the preceding). 

 c Tylostylus (of the 

 cortex). 



spicules of the same kind together with 

 smaller tylostyli. The cortical skeleton 

 proper consists of crowded fusiform sub- 

 styli arranged perpendicularly to the 

 surface, but immediately beneath and 

 closely associated with it is a thin 

 matted layer of mostly horizontally dis- 

 posed styli of the larger kind. Fibres 

 from the inner skeleton penetrate into 

 the cortex, spreading out slightly at 

 their extremities in a penicillate fashion ; 

 the terminal spicules of these fibres 

 usually project slightly at the surface. 

 The arrangement of the fibres imme- 

 diately underlying the cortex is one of 

 marked regularity. In the body of the 

 sponge, a series of equidistant parallel 

 fibres running upwards from the base is 

 most conspicuous, but in the processes, 

 a series of circumferentially directed 

 fibres external to these also comes into 

 prominence. The latter run undulat- 

 ingly and intercross so as to form a 

 wickerwork-like structure of very ele- 

 gant pattern. The specific name has 

 been bestowed in reference to this 

 feature. 



Spicules. — 



(i.) The larger oxea-like styli are 

 straight, and measure 660- 

 1200 X 12-22 p. 



(ii.) The smaller are usually slightly 

 curved and more distinctly 

 stylote ; they range in size from 

 220 X 6 to 350 X 9 }i. 



(iii.) The tylostyli (or subtylostyli) 

 are fusiform and usually 

 slightly curved. They occur 

 singly and in small bundles in 

 the ground substance. Size : 

 120 X 3 to 200 X 5 Jl. 



Loc. — North coast of New South 

 Wales, eight miles east of Sandon 

 Bluffs, 35-40 fms. ("Endeavour.") 



