95 



appear however in Hianlopora, RiujuUirUi (PI. V, fig. 2 a), Petalosiegiis (PI- IX, 

 figs. 8 a, 8 b) and .sometimes in Chai>eri<t. The ooecia are as a rule hyi)erstomiai, 

 and might be considered as free, i)ecause the endoorecium only has a small 

 portion of its basal wall in common with the frontal wall of the zooecium. 

 Whilst the endoooecium is always calcareous, the ectoooecium may be calcified 

 completely (Bicellaria ciliat(i) or almost completely (Dimetopia corniita), or some- 

 limes quite or partially uncalcified (Dcndrobeania Miirrdijtina. BiKjnlaria dissimHis, 

 etc.). In a smaller number of cases Ihc o(rcia are immersed either in kenozoii-cia 

 or in ordinary zocecia (yBugiila^ inirdhilis). With the exception of most Chaperia 

 species and of 'Membrnniporaf CarU'ri\ which on account of its pedunculate, 

 capitate avicularia must certainly be referred to this family, the colonies are 

 never incrusting and appear in a greater variety of forms of growth than in any 

 other family of the CljeilDstonuitd. Apart from such genera as GemelUtria, Notamia 

 and Siinnotum, in which the colonies may be considered as two-layered, colonies 

 with two layers are only found in Wdtersia militaris and Bimorphozoiim nohile. 

 Radical fibres appear in most genera and in very different ways (see Ihe synopsis 

 of the genera). 



This family, like the Aeteidae, presents a series of points of contact with the 

 Ctenostoimtid, and forms so to speak a connecting link between these and the 

 Cheiloslonuttd. This is nowhere more prominent than in the peculiar dimori)hism 

 in Dimorphozoiim nobile (PI. IV, ligs. 1 a— 1 e), as the zou>cia in the one layer of 

 the colony are built in quite the same way as in an Alcynnidiiwi, whilst in the 

 opposite layer they possess an operculum, avicularia and ocecia. For the rest, 

 however, the diaphragm in these zotecia seems to be Ctenostome-like. We should 

 also remember that an operculum is absent in species of the genus Bmjiiki, as 

 also that the diaphragm in Eiicrdled cheMd is said lo be built in the same way 

 as in the Ctenostonuitd. The generally slight calcification also agrees with this 

 view, and finally a series of forms in this family shows quite similar modes of 

 connection between the zoa'cia as those we know in the majority of the Cfeno- 

 stomdld. Thus, Bednia corresponds in this regard with the Ctenostome genera 

 Ardchnidium and Biiskid, whilst the stolon or stem, which consists of kenozoiecia 

 and which is widely distributed in the Ctenostomatd, is again found in ^Bkelldvid' 

 (jldbi-d, Biujidd (Stirpdrid) Hdddoni and B. (Stirpdid) cdrdibicd. 



When Busk, Hincks and other writers refer a number of genera of the 

 family (Eiwrdled, Ccmelldrid, Notdinid, Didijmid, Dimetnpid etc.) lo other families, 

 I lie reason is, thai these writers have laid greater stress on the form of colony 



' 'r.i. p. s'i 



