FAMILIES AND aENEBA OP THE MADREPORABIA. 49 



and Edwards and Haime are united, and the whole Astrfeidse are 

 subdivided into seven subfamilies. 



Although it is proposed to abolish the classificatory distinction 

 between the Astreeidse with entire and with dentated or ragged 

 septal edges, it is necessary to keep in view the method of growth 

 and increase of the forms. Milne-Edwards and Jules Haime 

 founded their classification of both of the groups, now united, 

 upon the principles of their gemmation and growth. Thus the 

 Eusmilinse, Ed. & H., or the Astrgeidae with entire septa, were 

 classified as Simple, Csespitose, Confluent, and Agglomerate ; and 

 the Astrgeidse with dentate septa, the Lithophylliacese, Ed. & 

 H., were grouped almost after the same manner into Simple, 

 Csespitose, Meandroid, Eissiparous, and to these was added the 

 agele of the budding Astrseaeese, These divisions or " ageles " 

 are fairly natural, and it is only rarely that some hard and fast 

 lines of distinction oppose the truth. Eissi]3arity is the rule 

 amongst the c8esj)itose and confluent Eusmilinae, and amongst 

 the csespitose and meandroid Lithophylliaceae ; but it is accom- 

 panied by more budding than has been hitherto admitted. More- 

 over the long serial calicos of the confluent and meandroid 

 forms seem to develop by simple growth from the calicular 

 ends quite as much as by an indefinite fissiparity. The great 

 break was between the Caespitose and Meandroid Lithophylliacese 

 with dentate and ragged septa. Thus the genera Mussa, Oken, 

 and Sympliyllia, Ed. & H., are very closely allied, and at one 

 stage they must belong to the Meandroid group ; but the early 

 life of the 3Iusscb is often passed in a caespitose condition of 

 growth. It is necessary to place these genera, the one at the 

 close of the Csespitose and the other at the commencement of 

 the Meandroid group. 



In the present classification, the Eusmilinse, Lithophylliacese, 

 and Astrseaeese, being absorbed in the family Astrseidse, the 

 ageles of Milne-Edwards and Jules Haime become subfamilies, 

 and their sections also. The simple forms of both groups are 

 united in a subfamily Astrceidee simplices-. The csespitose genera 

 of the Lithophylliacse and EusmiKnse become csespitose Astrseidse ; 

 and the meandroid Lithophylliacese and the confluent Eusmilinse 

 become confluent Astrseidse. The Astrseaeese or massive budding 

 group become AstrosidcB agglomerates gemmantes. 



It is evident that the genera which increase by stoloniferous 

 gemmation must form a subfamily, and that the dendroid forms 



LINW. JOTJBN. — ZOOLOGT, TOL. XVIII. 4 



