﻿SPONGES.- KALLMANN. 



273 



This species is represented by two dry and washed-out speci- 

 mens. The sponge, which is attached by an encrusting basal 

 disc, consists of a clustered mass of short erect tubes which 

 multiply both by branching and by the upgrowth of new ones 

 from the base. Branching takes place, typically, in such a 

 way as to give rise to an arrangement of the tubes side by side 

 in single, longer or shorter, series. The component tubes of 

 each such series may fuse with each other laterally so as to 

 form a plate with the tube-orifices in a single row along its 

 upper margin, or they are more or less free from one another 

 except at their bases. Anastomosis occurs freely wherever 

 tubes of the same or different series come 

 into contact. The two specimens are ap- 

 proximately equal in size : the slightly 

 larger is 75 mm. high and 100 mm. by 65 

 mm. broad. The free terminal portions of 

 the tubes in no case exceed 20 mm. in 

 length, and are 6 to 10 mm. in external, 

 and 3 to 5 mm. in internal, diameter. The 

 pseudoscula are of the same diameter as 

 the tubes internally. The texture, as 

 shown by washed-out specimens, is 

 similar to that of a Chalinine sponge. As 

 regards consistency, the sponge is com- 

 pressible and elastic, and fairly tough. 

 The colour varies, even in different por- 

 tions of the same specimen, from brownish- 

 yellow to dark-brown. 



The skeleton is a wide-meshed reticula- 

 tion of densely horny fibres of a deep 

 brownish-yellow colour, of which only the 

 main fibres contain a slender core of pauci- 

 serially (or sometimes even uniserially) 

 arranged small spicules. The main fibres 

 may (rarely) attain to 80 j( in stoutness, 

 but are usually less than 60 p. ; the dia- 

 meter of the connecting fibres varies from 

 10 to about 40 ]i. The former are dis- 

 tinguishable into two categories which 

 might be termed, respectively, primary 

 and secondary (or excurrent) main fibres, viz. : (i.) those 

 which ramify over the inner surface of the pseudoscular tubes 

 and form, with the aid of connecting fibres, a strong, irregu- 

 larly-meshed, supporting reticulation; and (ii.) those which, 

 arising as branches from the preceding, traverse the tube-wall 

 obliquely upwards and outwards to the exterior surface. The 

 last-mentioned, or secondary main fibres, rarely branch ; but. 



Fig. 60—0. tiibu- 

 losa. a Principal 

 sty li — the shorter, 

 intrafibral ; the 

 longer, interstitial, 

 b (?) Auxiliary sty- 

 lus. 



