REPORT ON THE MONAXONIDA. 



87 



this is afforded by Cladorhiza moruliformis, nobis, in which the piunse are placed close 

 together near the top of the main axis (vide woodcut, Fig. 1) ; being all of the same length, 

 and radiating in every direction, while the soft tissues of 

 the sponge occupy the spaces between them, they give 

 rise to a spherical head perched on the end of a stalk. 



But by far the most remarkable of the modifications 

 which the main skeleton thus undergoes are exhibited 

 in the various species which we have called " Crinor- 

 hiza" forms ^ (vide woodcut, Fig. 2). When this remark- 

 able adaptive form is present in its most typical condition 

 we have the central axis represented by a stiff, straight, 

 tapering root ; the bulk of the soft parts are condensed 

 into a small subglobular or cap-shaped " body," while 

 the pinnae are very long and slender, and are arranged 

 in a single whorl close to the top of the axis ; these long 

 processes are very numerous and radiate in all directions, 

 extending far beyond the body of the sponge ; they are 

 directed outwards and downwards, and their function is doubtless to prevent the sponge 

 from sinking into the soft mud on which it lies, for which purpose they are admirably 

 adapted. 



Fig. 1, 



Cladorhiza morulifonnis. Longi- 

 tudinal section of tlie head showing the 

 arraugenient of the skeleton ; «, axis of 

 stem and radial bands of fibres ; ca, capsule 

 of loosely disposed spicules, x 4. 



^%v 



■\ 



^^ 



m 



FlQ. 2.—Axoniderina mimhile. Vertical section, showing the skeleton arrangement in a typical " Crinorhiza " form ; 

 a, axis of stem ; a', axis of supporting processes ; c, cortical layer of amphiasters ; ch, choanosome (?). x 5. 



The Crinorhiza forms appear to be without oscula and pores, nor have we succeeded 

 finding flagellated chambers, although some of the specimens were in very fair 



1 Anil, and Mag. Nat. Hist., ser. 5, vol. xviii. p. 342. 



