STUDIES ON THE COMPAEATIVE ANATOMY OF SPONGES. 241 



as Ute does to Grantia. As, however, there appear to be no 

 intermediate stages known between Grantessa and Hetero- 

 pia, the latter genus appears to have just as much right to stand 

 separately as Ute has, and the same objection does not hold 

 good as in the case of Leucandra and Aphroceras previously 

 discussed. Even should the genus have to be abandoned, still 

 the name " Heteropidse^' may be conveniently retained for 

 the family. The only known species of the genus is H. 

 ramosa. 



Genus 15. — Vosmaeropsis, Deudy (4), fig. 19. 



Diagnosis. — Flagellated chambers spherical or sac-shaped, 

 never truly radial. Dermal cortex composed principally of 

 triradiates, without longitudinally disposed oxea. 



Remarks. — This genus stands in much the same relation to 

 Grantessa as Leucandra does to Grantia. The canal 

 system of Vosmaeropsis macera (fig. 19) affords an excellent 

 example of the " Sylleibid " type which characterises von 

 Lendenfeld^s genera, Polejna and Vosmaeria (10) j but I 

 have already expressed my opinion that the mere presence of 

 this type of canal system cannot be utilised for purposes of 

 classification, as it is found in several very distinct forms which 

 we cannot unite in defiance of the great structural differences 

 in their skeleton. It might be doubted whether Vosmaer- 

 opsis should be generically separated from Grantessa, as 

 this separation depends entirely upon the canal system; but, 

 although I do not consider the distinction between the 

 Sylleibid and Leuconoid types of canal system sufficiently well 

 marked to be utilised for generic purposes, I think we may 

 very conveniently thus utilise the much greater distinction 

 between the Syconoid and Leuconoid types, considering the 

 Sylleibid one, for purposes of classification, as belonging to 

 the Leuconoid division. 



I only know of three species which can be included in the 

 genus Vosmaeropsis, viz. V. macera (4), V. depressa (4), 

 and V, Wilsoni (4). 



