94 



less proximally on the basal surface of Ihc zooecium. The lateral walls always 

 independent, and each provided with 1 (rarely with 2) multiporous rosette-plate, 

 which is often partially uncalcified. The avictilaria when present dependent, most 

 frequently capitate, pedunculate, freely movable, more rarelj' sessile and in that 

 case often extremely long and slender. The iMvcia as a rule hyperstomial, free, 

 more rarely endozooecial and then as a rule covered by kenozo(i>cia. The colonies 

 free or creeping, generally branched ami frecjuently provided with radical fibres. 

 • With a few exceptions (e. g. Hiantopora and Cbaperia) the calcification in this 

 famil}' is very feeble, and the least calcified Cheilostoniala known are undoulitedly 

 the Beania species, of which some contain so little calcareous material that it is 

 only by using hydrochloric acid that we can make sure that there is any calci- 

 tication at all in their walls. Whilst the whole frontal wall in the Beania species, 

 in Dimorphozoiim nohile and Watersia mililnris. is membranous, in most members of 

 the family a larger or smaller portion of it is calcified and forms a gymnocyst, 

 which may sometimes, for instance in (icmcllaria loriatta and certain Corniicopinu 

 species, occupy two-thirds or three-fourths of the whole length of the zoa'cium. 

 From this gymnocyst in older zooecia there arises not so seldom a small secund- 

 ary cryptocyst (e. g. in Duhjiiua simplex, Geiiiellaria loricala, Deiulrobeania Miirnnj- 

 and). Except for the species of the genus Beania in which the individual zocecia 

 are connected by cylindrical tubes, two zoo'cia in the same longitudinal row are in 

 all other cases connected by a distal wall, which is always more or less ascending 

 from the basal towards the front wall so that the distal end of the lower zocjecium 

 projects more or less over the j)roximal end of the zocecium above. It is usually 

 furnished with a number of uniporous, more seldom with one or two multi- 

 porous, rosette-plates and not rarely {Bmjula, Halophila, Didijmia, Bicellariu, Bicel- 

 larina, Bnc/nlaria) the basal edge shows a peculiar angular bending (PI. Ill, figs. 

 1 c, 2(1, PI. V, ligs. la, 2 1)). Each lateral wall is as a rule provided with 1 or 

 rarely with 2 multi])oious rosette-plates. Except for the pore-ring they are as a 

 rule membranous, and it is therefore difficult to decide, from spirit-material, 

 whether they ai'e uni- or mulliporous. In all cases where they are calcareous, 

 e. g. in Dendrobeania Miirraijana, l)in}(irj>hi>zount nohile, Biujularid dissiniilis etc., 

 they are however multiporous. Whilst the dependent avicularia in most Cheilo- 

 stonuitd attain their greatest breadth where they are fixed to the zoa'cium, most 

 avicularia in this family are provided with a shorter or longer movable peduncle 

 or the ])roximal part of the avicularian chamber is slender pedunculiform. While 

 the first have tlie j)eculiar resemblance to a bird's head wliicli has given rise to 

 the name > aviculariiim» the others which increase gradually in breadth toward the 

 distal end have been described as trumpet-shaped. (>ommon sessile avicularia 



