362 REVISION OF THE MOXAXONID StONGES, 1., 



Topsent(46), in describing Clioiia celata, has drawn attention 

 to a number of points of resemblance between it and C. hixoriii, 

 and expresses the opinion that "un rapprochement entre les deux 

 especes est tout indique." The additional information which I 

 have furnished concerning the microscleres of the latter, shows, 

 how'ever, that there is not such a close analogy between the 

 spiculation of C. celata and that of C. hixonii as Topsent sup- 

 posed, and particularly is it questionable whether the oxea 

 " lisses, aceres aux deux bouts, legerement courbes, tres fins " of 

 the former are homologous with the acanthoxea of the latter. 



In their possession of a vestigial spiral flexure, and of spines 

 linearly and in some degree spirally disposed, the acanthoxea of 

 C. hixo7ni, as well as those of the next-described species {C. 

 hUea),* exhibit characters which render it practically certain 

 that they are derivatives of spirasters. They are, thus, quite 

 unlike the acanthoxea of such species as C. vastijica Hancock, C. 

 stationis Nassanow, and C. velans Hentschel, which are quite 

 devoid of any sign of spirality, which are provided with numerous 

 very minute uniformly distributed spines, and which frequently 

 exhibit a centro tylosis: the latter spicules, indeed, are regarded 

 by Topsent as belonging to the category of megascleres, I con- 

 sider it exceedingly probable, therefore, that acanthoxea have 

 originated in the genus Clio7ia in tw^o independent ways; and it 

 is possible that those of C. vastijica, etc., are derived from smooth 

 oxea such as do occur in some species of Cliona, and which 

 perhaps are of common origin with the tylostyli. 



Papillissa lutea. (PL xviii., figs.l, 2) 



Though I do not doubt that the several specimens labelled 

 Papillissa lutea, in Lendenfeld's handwriting, are genuine ex- 

 amples of the species, I am at a loss to account for the absence 

 of any reference in his description to the fact that they are 



* 111 Cliona areoiata (formerly known as Spirasfrdla artolata) also, of 

 which species I have seen a mounted section presented lo the Australian 

 Museum by Professor Deiidy, the acanthoxea are undouljledly spiraster- 

 derivatives; and, in the case of C. margaritifene Dendy(l5), an actual 

 transition between acanthoxea and spirasters has been recorded. 



