214 



smaller, sonielimes extremely smiill nores. A ervptocvst may be I'oimil pailly in 

 the shape of a senii-cireiilai- or semi-elliptical calcareous lamina, which from the 

 proximal margin of the primary aperture extends some way down the inner sur- 

 face of the frontal area, partly within the above mentioned fenestra'. No mar- 

 i;inal spines but sdmelinu-s sluul. aeropelalous, adoral spines and more or less 

 developed bilaminale spines. The aperture has a more or less strongly ehilinized 

 comiiound operculum, and the distal wall, consisting of a horizontal basal and 

 an obli(piely asciMiding frontal part, as well as the lateral walls, have a larger or 

 smaller luimber o! small, scattered, single-pored rosette-plates. Tlie znaria are 

 conneeled with a nundier of lalcial cliaiiihcrs. uh)sI often keno/oo'cia, fretpuMitly 

 to a certain extent uncalcilied, Ihe ty])ical nund)ei' of which is four on each side. 

 The second chand)er (reckoned from the distal end of the zo(vcium) is however 

 in a greater or snuiUer luuuber of /.oo>cia develoited into an aviciilnriniii. The 

 o<vci(t, usually situated on gonozocccia of nuire or less ])ei'uliar structure, are 

 endozo(vcial and nuiy be covered either by ordinary zoiecia or by kenozoircia. 



The free, highly branched colonies fui-nished with radical libies, the zoiecia 

 of which are all turned in the same direction, are jointed, consisting of internodes 

 which may contain 1 — ',\ zoa'cia. Most freijucnlly internodes with one and inter- 

 nodes with two zo(\'cia appear in the same colony, alternating in dilVerenl ways. 



The nmsl peculiar charactei- in this very natural and very distinctly delined 

 family is the presence of the above mentioned lateral chambers. Waters' 

 has I'alK'd the one, which in a greatei- or smaller number of zoo'cia is devel- 

 oped into an axicularium, the avicularian chamber* and the two contiguous 

 ones the »supra-aYicularian« and the inlVn-avieularian chamber . while he calls 

 the proximal one, which is independent of Ihe aviculariuiu, the jietlal ehamher<^. 

 However the name of avicularian chamber cannot very well be applied as a spe- 

 cial denomination of the above mentioned chamber, as it must he used in Ihe 

 ordinary sense of Ihe word. i. e. as the name of the chandier in all avicularia, 

 nor can it properly be applied with respect to the zo(vcia in which this cluuuber 

 is not develo])ed into an avicularium. For this reason I propose to call these 

 three chambers the ^-scapular', the supra-scapular- and the "infra-scapular* 

 chambers. Each lateral wall of a zoo'cium in eonneclion with the lateral chambers 

 mentioned has generally two separate groups of roselte-jtlates, a distal and a 

 proximal, the number of jilates in which most frequently varies between 10 and 4 

 but sometimes may be only one. hi the genus Hiiuhsivlld the proxinud group is 

 wanting and the distal one represented by 1 — 2 rosette-plates, hi the species of 



' 107. p HX 



