88 ORGANIC DEPENDENCE AND DISEASE 



menclatorial procedure. The Vioa prisca and its type being 

 undoubtedly worm borings must take a more appropriate 

 designation. 



We are referring to Clionolitlies, the form C. radicans, 

 which enters brachiopod shells by a simple perforation 

 and once within the shell substance produces a radiate and 

 arborescent or root-shaped colony. Shells are often quite 

 riddled by these colonies, which may maintain individual 

 independence, no matter how numerous, though at times in 

 a thick shell, galleries may so overlie one another as to ap- 

 pear massed or felted. It is this form of sponge which may 

 be taken as the type of the genus. 



Clionolithes palmatus, which has been found only in the 

 soft shales of the Portage group (Upper Devonian), pre- 

 sents a somewhat different aspect from C. radicans in its 

 broad, sparsely branched or palmate tunnels. 



Clionolithes reptans is a filamentous and vagrant tube 

 tunneling just beneath the surface of the host-shell. It is 

 common in brachiopod shells of the Lower Devonian and it 

 is assigned to the sponges because there seems no better 

 present interpretation of it. 



Of entirely different type and of much greater size is a 

 perforating sponge which we observe in the Middle De- 

 vonian Stromatoporas of Iowa. In this there is a large 

 spherical central body from which stout cylindrical arms 

 radiate into the coral substance. The formation of the 

 tunneling appears to begin with the gradual burial of the 

 round centrum with its branches and the subsequent exca- 

 vation of additional tunnels by later outgrowths of the 

 colony. These sponges have been found both as depres- 

 sions at the surface of the coral and as completely buried 

 bodies within the coral substance and revealed only by cut- 

 ting. 



This parasitic sponge we shall designate Topsentia de- 

 vonica. 



Worms. The boring worms of the existing fauna have 



