488 



KkVLSION of the AX1NELLIU.4:, i., 



fibres in the central region of the branches, but comparatively 

 scarce and somewhat irregular in occurrence towards their 

 surface The main fibres attain a stoutness occasionally of 

 nearly 200/x in the axial region of the skeleton, but diminish in 

 diameter periphei'ally to between 60 and 1 00/x; they are composed 



of somewhat looselvand irregularly 

 pacUed spicules united by abundant 

 spongin-cement. The connecting 

 fibres are usually less than 50/i. in 

 stoutness and are composed almost 

 entirely of spongin. The spongin 

 shrinks considerabl}' on drying, so 

 that in the dried skeleton the stout- 

 ness of the fibres is much less than 

 stated above. The skeleton seen 

 in its entirety (PI. xxxix., fig 6,> is 

 of a golden-yellow colour. 



Jlegasc/ei-es. — The differences be- 

 tween the megascleres of the stalk 

 and of the branches are more mark- 

 ed than in any other of the species 

 herein described, the former con- 

 sisting almost entirely of sharp- 

 pointed oxea, ranging from seldom 

 less than 250 up to 460/a in length 

 and up to 16/x in stoutness, and 

 very similar in form and size to 

 those of 7'. digita/us var. strongy- 

 latus, while the latter are strongyla 

 and more or less blunt-pointed oxea 

 — the strongyla being if anything 

 Text-fig.9. — Tmchycladufi pnslu- somewhat the more numerous — 

 /o.s7(.s. Megascleres : a, from the ranging in length from occasionally 

 .stalk; h, from the branches. j^^^ ^j^^^ j^q^^ ^^^ ^^ ^j^^^^. 3^0 or 



330//,, and seldom exceeding 8-5 or 9/x in stoutness. Occasional 

 stvli are met with, which are most frequent among the pedun- 

 cular megascleres; among the latter also anisoxea are not 



uncommon. 



