REPORT ON THE MONAXONIDA. 99 



Genus Chondrocladia, Wyville Thomson (Pis. XX., XXL). 



1873. Chomlrodadia, Wyville Thomson, The Depths of the Sea, p. 188. 



1 880. Clailorhua (j)artt), Schmidt, Die Spongien des Meerbusen von Mexico, pt. ii. p. 83. 



Of varying, but usually symmetrical form. Skeleton usually consisting of a central, 

 erect axis of spiculo-fibre, which may or may not be branched, and from which arise 

 longer or shorter processes, also composed of spiculo-fibre. The chief megasclera are 

 stylote and often attam a great length. The characteristic microsclera are isochelse, 

 with three or more teeth at each extremity and a curved shaft expanded laterally near 

 each end into wing-like processes. Sigmata may also be present. 



The genus was founded in 1873 by Sir Wyville Thomson (loc. cit.) for his 

 Chondrocladia virgata ; but he gives no generic diagnosis. 



The two genera Chondrocladia, Wyville Thomson, and Cladorhiza, M. Sars, 

 appear to be closely allied, differing only in the form of the chelae, which in the one 

 case have the two ends unequal and in the other equal, and, as already pointed out 

 (p. 86), Schmidt includes both under the name Cladorhiza. 



The Chondrocladia^ are also deep-sea sponges, and may acquire the " Crinorhiza " 

 form ; they are not nearly so well represented in the collection as is the genus 

 Cladorhiza. 



The geographical distribution of the genus is extended by the results of the 

 Challenger voyage from the North Atlantic to the Southern Ocean and the Pacific, 

 and the vertical distribution to nearly 3000 fathoms. 



Chondrocladia concrescens (?), Schmidt, sp. (PI. XX. fig. 12 ; PI. XXI. figs. 7, 

 7 a, 12). 



1880. Cladorhiza concrescens, Schmidt, Die Spongien des Meerbusen von Mexico, pt. ii. p. 83, 



pi. X. figs. 8, 9. 



Want of evidence, due both to the fi-agmentary nature of the Challenger specimens 

 and to the incompleteness of Schmidt's original account, makes the identification of this 

 species doubtful. 



The Challenger specimens (PL XX. fig. 12) consist of five stalks, four of which have 

 their ends inserted into sockets in a thick, fleshy mass strongly resembling mammalian 

 hyaline cartilage in appearance, while their other ends are free. The fifth stalk is 

 separate from the others and has a lobe-like, fleshy mass adhering to one end. It is 

 the narrower ends of the stalks which are inserted into the soHd fleshy masses, while the 

 broader ends are free, but have evidently been attached ( ? to the main stem) when the 



