100 R. M. Brydone — New Chalk Polyzoa. 



This species was found in the zone of J/, cor-anguinum at Seyington, 

 in Hants. It has obvious relationship with the figure of Flustrellaria 

 granulosa, D'Orb.,' but that figure must be quite unreliable, as Canu, 

 in his " Kevision", unites the type with Flustrellaria de7itata, a widely 

 different form. 



Membranipora sandalina, sp. nov. (PI. YI, Pig. 10.) 



Zoarium unilaminate, incrusting. 



Zoceeia of medium size, average length '6 mm. with small oval 

 apertures from '3 to '35 mm. in length, tapering considerably to the 

 flattened anterior end and surrounded by broad, rather indefinite 

 inward-sloping margins, which arise out of a common crust rather 

 sharply in the anterior part, but die away posteriorly : at the anterior 

 end there is a pair of small pores high up on the inner side of the 

 margin just behind the end of the aperture, and a pair of tiny pores 

 on the outer edge of the margin at its corners just outside the points 

 from which the ooecium starts : the pair of small pores occurs with 

 very great regularity, and as the pair of tiny pores can almost always 

 be detected when the presence of an ooecium assists the search, 

 it also is probably always present : at the posterior end of the 

 aperture there is, or rather there should typically be, a central 

 hollow protuberance rather like the front halt of a sandal, laid with 

 the toe pointing away from the aperture; this is actually the case 

 with zooecia which do not have to accommodate the ooecium of 

 another zoceciura, and sometimes even when this accommodation 

 has to be provided ; but in the latter case, as a rule, the protuberance 

 is displaced by the ooeoium and splits into two rather smaller 

 lateral ones. 



Oosoia very regular in occurrence, long and helmet-shaped, with 

 apertures cut a long way back. 



Avicularia probably of two kinds: {a) accessory, the protuberances 

 above described; {l) vicarious, rather scarce, of the hour-glass type, 

 elongated and narrow, with very little infold in the centre, no 

 internal front wall in the lower lobe, and an inflated external front 

 wall at the posterior end. 



This species, too, occurs in the zone of M. cor-angumum at 

 Gravesend. The two preceding species can obviously be referred to 

 one of the two groups mentioned above. This species not only 

 combines the characters of the two groups, but exhibits an actual 

 passage of the character of the second group into a very plausible 

 imitation of the character of the first group. 



EXPLANATION OF PLATE VI. 

 Pig, (All figures x 12 diams.) 



1, 2. Pseudostege concursa. Zone of A. qtiadrattis. Sbawford, Hants. 



3. ,, ,, Zone of B. mucronata. Portsdown, Hants. 



4. Cellepora diastoides. Trimingham. 



5, 6. Membrajiipora Seafordensis. Seaford, Sussex. 

 7, 8. ,,' multifissa. Gravesend, Kent. 



9. ,, . Sevmgtonensis. Sevington, Hants. 



10. ,, sandalina. Gravesend, Kent. 



1 Pal. Cret. Fran?., vol. v, p. 525, pi. 725, figs. 1-4. 



