THE ANTHOZOA 



45 



much rciluccd, h;ivo no filaments and no niiisclo hamier.s (Fig. 

 XXI. o). Thus wo find that wliilst twolvo i)i-imaiy mesenteries 

 are present, four of these, namely, those Avhich arc absent in 

 Edwardsia, lai; l)ehind the others in size and ini])ortam'e. 



Wo are justified, therefore, in regarding the Edwardsiio as 

 the nearest living representatives of the ancestor of the six-rayed 

 Actinians. 



Fin. xxr. 



l.—Eihriirihiadiiparcilii, Pane. (Aftor A. Aiulrns.) 



•2. — Tniiisvorso .soctioii t)irou)(li the Htoiiiodii'iil region of Kd ward sia, Hhowing llio oiglit niosoii- 

 tories, ami tlie nrniiiKoniiMit of tlin niusclo Imnncrs. ,«, sulcus ; hI, sulculus. 



a. — //((/c((m/«( nitlmmitiihi, Auilr. (AI'tiT A. Anilrcs.) 



4. — TriuisviM'.so si^trtion llirounh llio sloniodinil ri'^ion of Ildtrnm^Ki, showiiiR twi'lvo coniili's of 

 coniploto primary nicHcntiiries and six couples of ndnuto inconiploto nio.st'iiU'ries in tlie oxocooles. 

 (/hi, directive ni(!senteries. 



."). — Transverse section of the same species below the region of the stoinodaeuin, showinn six 

 fertile inesentories— 1, i ; n, ii ; iii, in ; the sterile snlcnlar directives iv, iv, bearing lllanients, 

 and the retlucod niosontorios, v, v, and vi, vi, of the (Irst cycle. 



To the group of six-rayed Actinians we must now add the 

 largo assemblage of forms, both single and colonial, which have 

 hitherto been classed apart as the Madreporaria or stony corals. 

 Researches made by various authors in recent years have shown 

 that the anatomy of a Madrcporarian coral, leaving the skeleton 

 out of the question, is in all essential ])articulars identical with 

 that of such a form as Aditiia ('(/nina. IT. V. Wilson has further 

 shown (98) that in the coral Manicina arcolata the sequence of the 

 development of the first six pairs of mesenteries is identical with 

 that of Khodactis and Halcampa. Such being the case, it is no 



