430 A. W. WATEES ON FOSSIL CHILOSTOMATOUS 



which is drawn in order to explain it. "When snch species are 

 decalcified, the oval border of this plate is still distinguishable, 

 and we can also trace a similar oval boundary in other species 

 where there is no calcareous plate. This is the case in G. margari- 

 tacea : but perhaps this species gives us a clue ; for an oval border of 

 about the same size as that of C '. ponderosa is clearly seen, and here, 

 from the examination of decalcified specimens, there seems to be a 

 chamber of which tbe boundary is indicated by the oval line, and 

 the notch of the aperture does not represent a sinus, but apparently 

 is an opening into this chamber. I hope that those who have the 

 opportunity of obtaining living specimens will examine this point. 



As in so many genera of Bryozoa there is an avicularium or pore 

 below the oral aperture, may we not look upon the typical Bryozoa 

 as having a suboral chamber sometimes closed with an avicularian 

 cover, sometimes without, and with the opening sometimes closed 

 up to the oral aperture ? and may not even the adventitious tubules 

 of Diastopora obelia and also of some fossil Bryozoa have the same 

 origin ? 



To the specific description I have to add an avicularium opening 

 laterally, at about the height of the top of the aperture, and an oval 

 protecting calcareous plate on the ventral side of the zooecium below 

 the fenestras, which are thereby half closed. 



4. Oatenicella elegans, var. btjskii. 



Oatenicella elegans, Busk, var. Buskii (Thorns.), "Waters, Bry. 

 from S.W. Victoria, p. 317, pi. xvi. figs. 42, 43. 



5. Oatenicella solida, Waters. 



Oatenicella solida, Waters, loc. cit. p. 318, pi. xvi. figs. 37, 38. 



6. Oatenicella internodia, Waters. 



Oatenicella internodia, Waters, Bry. from S.W. Victoria, p. 318, 

 pi. xvi. figs. 78, 79. 



In specimens from Muddy Creek, Waurn Ponds, and Bird Kock, 

 the avicularia are rather larger than in the one I figured from S.W. 

 Victoria. There is also a contraction near the lower part of the 

 oral aperture on each side. 



Oatenicella internodia, var. angustata. 



Prom Bird Rock there are two very interesting specimens, which 

 in the shape and size of the zoarium are similar to other specimens of 

 C. internodia ; but on the dorsal surface, instead of the " irregular 

 oval depression," there is a long and broad vitta near the outer 

 border, about the size of that of 0. elegans, thus showing that the 

 physiological signification of the vitta and broad depression is iden- 

 tical. The front surface is not quite so well preserved, and is more 

 difficult to decipher ; but here also the oval depressions have be- 

 come narrower, and are, in fact, replaced by narrow vittae, and the 

 central band is replaced by a smooth surface. 



It is possible that some may have questioned whether I was 



