2 R. M. Brydone — Neiu Cretaceous Polyzoa. 



instance of the primary stage, but it is probably represented in 

 Fig. 7, and consists of zocecia with distinct bluntly pyriporiforni 

 side walls, flatly arched front walls, pierced by five pairs of well- 

 marked slits extending from the edge about a third of the Avay 

 across, and a flatly semicircular aperture with slightly concave and 

 upturned posterior lip formed by the broad unthickened margin of 

 the front wall; the anterior end of the zooecium rests on the rising 

 external wall of the succeeding zooecium, and thins out against it ; 

 small distinct avicularia are lodged in the interzooecial depressions; 

 in the secondary and normal stage the posterior lip of the aperture 

 thickens and fuses completely with a pair of avicularia at the corners 

 of the aperture and extends backwards a little way over the front 

 wall in a blunt triangle and forwards on either side of the aperture 

 on to the sides of and round the ooecium so as to form a platform level 

 (except for the swelling due to the ocecium) and standing only 

 slightlv above the front wall in the middle line, but considerably 

 above it at the sides, and encroaching on it more or less all round, 

 but especially at the posterior end ; the result of this encroachment 

 is that only three of the pairs of slits usually remain visible and 

 then only in reduced length ; there is generally more or less of 

 a depression in the centre of the anterior lip of tlie secondary 

 aperture. 



Ocecia invariably present in the secondary condition and evidently 

 highly globose, but without any definite outline ; aperture sunk 

 below the general surface, so tliat its free edge is only partially 

 visible. 



Avicidaria.^{a) Niciixious, average length 'So to '6 mm., scoop- 

 shaped with approximately parallel side walls and rounded ends; 

 the aperture appears to be bounded by the side walls in the posterior 

 part, but anteriorly it tapers away and a narrow internal front wall 

 appears; there are remains of a transverse bar across the posterior 

 end of the aperture ; they occur rather freely along the edge of the 

 zoarium, and not infrequently in the body of the zoarium, where 

 they are deeply sunk, [h) Accessory, in the primary condition 

 apparently beak-shaped and distinct; in the secondary • condition 

 wholly merged in the general mass, leaving only the broadly arrow- 

 head-shaped apertures visible ; a pair occur very regularly at the 

 posterior corners of the aperture and another pair much less 

 regularly at the anterior corners. 



This species is very rare; I have only seen one specimen, from 

 the zone (restricted) of A. quadraUis at Shawford, Hants. But for 

 its vicarious avicularia it would form a very perfect link between 

 Membraniporella suhcastriim, Bryd.,^ and M. castrum, Bryd.^ 

 Membraniporella. Bedhamptonensis, sp. nov. (PI. T, Pigs. 3-5.) 



Zoarium unilaminate, adherent. 



Zocecia distinct, average length -65 to -7 mm.; side walls strongly 

 overarching, front walls arising within the edges of the side walls, 

 flatly arched and pierced by five or six pairs of very short, often 



^ Ante, p. 494. 



2 Geol. Mag., 1909, p. 398. 



