590 



DR. R. VON LENDENFELD ON THE SYSTEMATIC [DcC 21, 



(4.) 



(6.) 



("With cylindrical chambers 5. 



L With spherical chambers (6,) 



{Chambers radial, opening direct into gastral 

 cavity 4. Syconidw. 

 Chambers opening into exhalant canals which 

 lead into the gastral cavity 5. Sylleibidm. 



Exhalants lead into oscular tubes 6. Leuconidm. 



Exhalants open direct on one side of the lamel- 

 lar sponge ; inhalant pores on the other 

 side exclusively 7. Teichonidcs. 



(2.) 



"■1 



With hexact spicules and thimble-shaped 



chambers 7. 



Without hexact spicules, with sac-shaped or 



spherical chambers (8.) 



The spicules remain isolated or partly coalesce 



afterwards irregularly 9. 



The supporting spicules early coalesce in a 



regular Dictyonid manner (10-) 



Hexaster in the interior 11. 



No hexasters, but amphidiscs (12.) 



Hypodermalia hexact sword-shaped, with centri- 

 petal radial ray longest; no pinnulse 8. Euplectellidce. 



Pumulie in the gastral and dermal surfaces ... 9. Asconematidce. 



Dermalia without centripetal ray ; no pinnulse 10. Eossellidm. 



(12.) With numerous pinnulse 11. Hyaloiiematidce. 



(10.) { 



•{ 



13, 



15. 



With uncinates 



Without uncinates 



With radially situated clavulse 



With radially situated scopulce 



Branched and anastomosing tubes ; the skeleton- 

 net forms several layers 



Branching tubular or calyculate, honeycombed ; 

 cavities traversed by reticular membrane . . . 



Calyculate or expanded, traversed transversely 

 by funnel-shaped canals opening alternately 

 on one or other surface 



Canals irregular, traversing the dense dictyonal 

 skeleton obliquely or longitudinally ..". 



13. 



(14.) 



12. Farrcidm. 

 15. 



13. EuretidcB. 



14. Melitiionidm. 



15. Coscinoporidce. 



16. Tetrodictyidm. 



(14.) Meandrically winding tubes 17. Meandro&pongidm. 



' With cartilaginous ground-substance and sphe- 

 rical chambers. Spicules polyact, tetract, 

 lithistid, tylostylote, or stylote, never ce- 

 mented with spongiu. Askeletous forms 



with spherical chambers 16. 



1.) \ With soft ground-substance, spherical or sac- 

 shaped chambers, Spicules monaxon, never 

 tylostylote, cemented witli spongin. Or ske- 

 leton composed of horny fibre without proper 

 spicules. Askeletous forms with sac-shaped 

 chambers (17.) 



