Mr. A. W. Waters on Australian Bryozoa. 89 



avicularia, and vibracula also agree ; but, on the other hand, 

 the internodes are short, with usually only three pairs of 

 zooecia. 



11. Ganda arachnoides, Larax. (PI. IV. tig. 7.) 



Canda arachnoides, Busk, Brit. Mus. Cat. p. 26, pi. xxxiii. ; * Chal- 

 lenger ' Rep. p. 25. 



A specimen from La Perouse has few avicularia, and in 

 large pieces of C. arachnoides I have noticed that some parts 

 will be found without avicularia, while in other parts they 

 are abundant. 



The increase at the dichotomization, which must often 

 have been examined, does not seem to have been described. 

 Between the two rows of zooecia an additional one is formed, 

 and from this two chitinous tubes are given off which are 

 curved forwards to the inner zooecium of a new branch. 

 The other zooecia are formed direct from the ordinary zooecia. 

 This seems to be the way in which growth takes place in 

 most of this group, as already seen in Cellularia cuspldata., 

 where in the same way the new branches spring by means of 

 a chitinous connexion from the central cell, and the two side 

 cells are continuous, though rather modified in shape ; and 

 here, as in some other cases, the articulation does not exist 

 at first, or only partially so, and there is calcareous continuity 

 until the movement of the water causes a fracture at the joint. 

 I have pointed out (Quart. Journ. Geol. Soc. vol. xxxvii. 

 p. 320) that the calcareous wall of Cellaria is at first con- 

 tinuous, but is in the same way fractured as growth pro- 

 gresses, some species retaining the continuity longer than 

 others, so that perhaps this may be of specific value. 



The oral aperture occurs in a round opening at the lower 

 part of the apparent aperture, and on this account I think there 

 is ground for separating Canda from Caherea, which has a 

 distinct operculum * closing a rigid oral aperture. This never 

 seems to have been fully figured, although of great importance, 

 perhaps sufficient to separate it from the family Cellularidse. 



Log. Bass's Straits ; Timor ; New Zealand {B.) ; Tas- 

 mania ; Geelong ; Port Phillip Heads ; La Perouse. 



12, Caberea Boryi (Aud.). 

 Crista Boryi, Aud. Voyage dans I'Egypte, pi. xii. fig. 4. 



* " On the Use of the Aviculariau Mandible,'' &c., Trans. Micros. Soc. 

 ser. 2, vol. v. pi. xiv. fig. 15. 



