52 



MR. A. W. WATERS ON TERTIARY CHILOSTOMATOUS 



two layers ; the avicularium is smaller, but the opening on the 

 mandible is larger ; the ovicell is smaller and more concealed. 

 In this also there is a similar perforation, and also, in some cases, 

 others round the edge of the cell ; but this seems to be rare. 



The fossils from Napier,' Waipukurau, " Whakati," and Trig's 

 Station agree with this last ; and while some specimens may have 

 an avicularium to almost every cell, in others they are seldom found, 

 and in one case they seem to be altogether absent. In many zocecia 

 there is a projecting boss, which seems to be imperforate, replacing 

 the avicularium. 



These two forms are evidently closely allied to M. coriacea, but 

 differ in not having a knob. - The " knob " of M. coriacea forms a 

 chamber which communicates with the interior by means of a rosette- 

 plate. (I have already, in a Eeport to the British Association on 

 the Naples Zoological Station, 1880, pointed out: that rosette-plates 

 occur at the base of the spines of Memb. cervicornis.) It is also 

 allied to Micropora lepida, Hincks, to which it is very similar in 

 appearance when there is a row of pores round the edge. The 

 mandible of M. coriacea has a central ridge from the beak, and the 

 same structure is seen in the other two species. 



22. Membraniporella nitida, Johnst., var. (PI. VII. i g. 18.) 



There are two fossil specimens from Waipukurau, whicl^ differ from 

 recent ones from " New Zealand" only in havirq; four bpines, and 

 this is probably not a very important character. The lower lip is 

 thickened, and this is the case in a recent specimen from Capri ; 

 the ovicell has often more or less of a keel, and has a ridge which 

 cuts off the lower part, and in this respect resembles M. di stains, Mac- 

 Gillivray (Descrip. of New or Little-known Polyzoa, pt. 2, pi. ii. 

 fig. 5). In the fossils there are no avicularia, whereas in a recent 

 specimen of this variety from New Zealand there is a large spatulate 

 vicarious avicularium, like that figured by Busk for Cribrilina philo- 

 mela, var. adnata. The costae vary from five to eight on a side. 



We seem now to have various links, recent and fossil, between 

 C. Jigularis, C. philomela, and Membraniporella nitida, and there is 

 no hard and fast line between Cribrilina and Meinbranipordla. 



Loc. Living : New Zealand. Fossil : Napier, Waipukura'U. 



23. Cribrilina monoceros, Busk (non Eeuss). 



Lepralia monoceros, Busk, Brit. Mus. Cat. p. 72, pi. xci ii. figs. 5 

 and 6 ; MacGillivray, Zool. of Victoria, decade iv. p. 32 , pi. 38. 

 figs. 1 and 2; Eidley, ZooL Coll. 'Alert,' Proc. Zool. Bote. 1881, 

 p. 51. 



Cribrilina monoceros, Hincks, Ann. & Mag. N. H. ser. 5, vol. viii. 

 p. 57, pi. iii. fig. 6, and vol. xiv. p. 279, pi. viii. fig. 5 ; Waters, 

 Q. J. G-eol. Soc. vol. xxxviii. p. 507 ; Busk, Eep. of ' Challenger' 

 Polyzoa, p. 133, pi. xix. fig. 8. 



In the Napier fossil the size of the aperture corresponds wit h that 

 of recent specimens and of the Bairnsdale fossil. In a :rccent 



