﻿SPONGES.-HALLMANN. g-?" 



(4). Form (d). (PI. xxxiv., fi 



&• 



ihe specimen now to be described is perhaps sufficiently 

 distinguished in several respects from the three preceding to 

 permit of its being regarded as representing a variety of the 

 species, or even (if its differences be constant), as representing 

 an independent species. Its chief distinctive characters are : 

 (i.) The absence of chelee ; (ii.) a minute wartiness of the basal 

 ends of the auxiliary tylostyli ; and (iii. ?) a restricted range of 

 length of the toxa. 



The specimen, from which the stalk (save for a small por- 

 tion) is missing, measures 90 mm. in height. The branches 

 are, for the most part, irregularly cylindrical, and average 

 7 mm. in diameter. The primary branches, as in the specimen 

 of form (c), exhibit a kind of bilaterality expressing itself in a 

 tendency towards a distichous arrangement upon them of the 

 short secondary branches. The characteristic surface-eleva- 

 tions sometimes assume the form of short ridges, but usually 

 they are rounded and somewhat wart-like. There is a distinct 

 but very thin dermal membrane. The colour (in alcohol) is 

 purplish pink ; this colour, however, is confined to a thin 

 superficial layer of the sponge, the inner parts being yellowish 

 grey. In life, the specimen was brick-red. 1 



Megascleyes. — 



(i.) The principal styli vary in length from 100 to 340 fi, 

 and in diameter up to 1 1 ji. The smallest approxi- 

 mate extremely closely in size and shape to the acces- 

 sory styli. A fair proportion of them are slightly 

 expanded at the base to form a faint knob. 



(ii.) The accessory spicules vary in form from simple styli 

 to tylostyli. Under ordinary powers of the micro- 

 scope they appear quite smooth ; but under higher 

 powers a barely perceptible roughening of portions 

 of the surface, more especially towards the basal ex- 

 tremity, is occasionally to be observed. Their length 

 varies from (rarely so small as) 45 yt to somewhat 

 over 90 }i, but seldom exceeds 80 }i ; the stoutest may 

 attain to 4 /i, though a very considerable proportion 

 of them are less than 2 f( in diameter. 



(iii.) The auxiliary tylostyli, though normally straight, 



are very often more or less curved. A peculiarity 



■ which appears to be characteristic occurs in connec- 



1 The specimen is one of a large number of sponges collected in Port 

 Phillip and presented, together with a list of their colours in life, by the 

 late J. Braccbridge Wilson, M.A. 



