BY £. F. KALLMANN. 367 



by a relatively very broad layer or wall of collenchymatous tissue, 

 which, to the naked eye, has a somewhat gelatinous and translucent 

 appearance as compared with the surrounding denser tissue. The 

 specimen, which is preserved in alcohol,, is of a dull yellowish- 

 white colour; it is of rather soft consistency, and is very easily torn 

 asunder. In the living state, according to the original description, 

 the colour is a bright orange-red, which is more pronounced and 

 mtense on the surface than in the interior. 



In the body of the sponge, the main skeleton consists of a rather 

 dense and confused, somewhat renieroid, reticulation of single 

 spicules and of spicule-bundles (or short, paucispicular fibres), 

 traversed at close intervals by well-defined, multispicular fibres 

 (usually less than 50/x in stoutness) running, for the most part, in 

 a surfaceward direction; scattered through the reticulation are 

 raphides, which occur both singly and in bundles. In the processes, 

 however, in correspondence wdth an increase in development of the 

 multispicular fibres, the reticular component of the skeleton is 

 more or less reduced, and, in their more central region, may occa- 

 sionally disappear altogether; in the latter case, the skeleton con- 

 sists almost exclusively of closely approximated, longitudinally- 

 running fibres, the diameter of the stoutest of which may exceed 

 200/x. The fibres are everywhere composed of loosely aggregated, 

 parallel styli, together with a small proportion of tylota. Spongin 

 is entirely absent. In the extensively developed collenchyma sur- 

 roimding the canals, the only skeletal elements are singly scat- 

 tered raphides and tylota, the former abundant, the latter usually 

 scarce. The ectosomal skeleton consists of closely approximated, 

 slightly divergent, vertical tufts of tylota, with numerous raphides 

 scattered between; the tufts often, though not usually, are j^ro- 

 longed inwards into loose straggling strands (of tylota) connect- 

 ing with the multisi^icular fibres of the main skeleton ; but in many 

 places, especially where the dermal layer is immediately underlain 

 by collenchyma, a discontinuity exists between the dermal and main 

 skeletons, which is very marked. 



Spicules. — (rt)The styU are (as a rule, slightly) curved, or rarely 

 straight spicules, of nearly uniform diameter throughout their 



