TERTIARY CTCLOSTOMATOUS BRYOZOA FROM NEW ZEALAND. 



337 



25. On Tertiary Cyclostomatous Bryozoa from New Zealand. 

 By Arthur Wit. Waters, Esq., E.G.S. (Head May 11, 1887.) 



[Plate XVIII.] 



The Chilostomata have already been described in this volume of 

 the Journal, p. 40, and therefore it is not necessary to repeat 

 particulars about the localities. 



This part I have kept back, hoping that the results of the 1 Chal- 

 lenger 7 Expedition might throw some light upon this unsatisfactory 

 suborder ; but Mr. Busk's second part of the Report is a great 

 disappointment in this respect, as only thirty-three species are 

 recorded, and these are for the most part well known and common. 

 In fact, the results of this great expedition do not seem, so far as the 

 Cyclostomata are concerned, to exceed what I presume a specialist 

 might, after a storm, collect in a few morning walks in the neigh- 

 bourhood of the Sydney Harbour. 



We do not seem to make much progress with the discouraging 

 Cyclostomata, or to obtain fresh characters upon which classifications 

 can be based, and in fact there are a few New-Zealand fossils 

 concerning which I cannot pronounce a definite opinion as to whether 

 they really belong to the Bryozoa or not. However, although not 

 satisfied with our means of classification, any fossils which can be 

 readily recognized should be described, as, besides being useful 

 strati graphically, fuller acquaintance may gradually set us in the 

 right lines. 



I would propose that we should divide the Cyclostomata into two 

 subdivisions, namely, first, the Parallelata, or those in which the 

 surface of the zoarium is to a considerable extent formed of the 

 lateral walls of the zocecia, of which Crista, Entcdopliora, Diasto- 

 jpora, and Tubulipora may be taken as types ; and, secondly, the 

 Hectangulata, or those in which the zocecia or cancelli open for the 

 most part at right angles to the axis or surface of the zoarium or 

 subcolony, of which Eeteropora, Lichenopora, &c. may be taken as 

 typical. 



We are met with the fact that there are several cases of genera 

 having similar zoarial appearance which must be separated into 

 these two divisions ; for instance, there is the true Idmonea, as 

 /. Milneana, with the zocecial walls parallel for the greater part with 

 the zoarial axis and the wall minutely perforated ; and, on the other 

 hand, with a similar zoarial appearance, Grisina cancellata has 

 medium-sized interstitial tubes between the zocecia, both opening at 

 right angles to the surface. 



We have already seen Cyclostomata and Chilostomata quite similar 

 in mode of growth, and in fact in this respect resembling even 

 animals of other classes, so that we need not be surprised at finding 

 such similarity in two subdivisions. 



There are cases where, in badly preserved fossils with large pores, 

 it may be difficult to distinguish whether these are interstitial or 

 merely perforations in the shell-wall; but when sections can be 



