') 



I 



6 



J 



ACTIN0Z0A. 



207 



7 



8 



9 1 



10 



Sclerenchyma reticulate. The- 

 cae not distinct from the sur- 

 rounding coenenchyma. 



Sclerenchyma simply porous. 

 Thecse distinct. . • 



Synapticulae present. No dis- 

 sepiments. .... 



SynapticulaB absent. 



Dissepiments in general numer- 

 ous. Coenenchyma absent, 

 or formed only by the deve- 

 lopment of the costae or epi- 



theca. . 



Dissepiments few or absent. . 



Coenenchyma compact, abun- 

 dant. . 

 No coenenchyma. . 



Family n. Poritidje. 

 Family 12. Madreporidje. 



Family 13. Fungidje. 



9 



Family 14. Astrjeid^e. 



. 10 



Family 15. Oculinidje. • 

 Family 16. Turbinolid^e. 



IS 



In addition to those her e defined, Milne Edwards 

 has distinguished four other families of Aporosa, 

 which inosculate, so to speak, between the primary 

 groups just mentioned. The first family, Das- 

 midce, includes but a single genus, closely related 

 to the Turbinolidce, from which it differs in the 

 peculiar modifications of its septa. Each of these 



represented by three vertical laminae, united 

 only along their external margin. A second 

 family, Sty lophor idee, appears as a transitional 

 group between the Oculinidce and Astrceidce. As 

 in the former, there is a well-developed coenen- 

 chyma and few dissepiments ; but, on the other 

 hand, the surface of the coenenchyma is echinu- 

 late, while it is smooth in the Oculinidw, and the 

 thecse of the corallites do not, as in that family, 

 increase endogenously, so as almost to obliterate 

 the loculi. Another osculant family, Echino- 

 poridcB, still more closely resembles the Astrceidce, 

 differing therefrom chiefly in the possession of a 

 foliaceous, basal coenenchyma. But one genus 



