SCHIZOPORELLA BIAPERTA. 255 



The cells are decidedly convex and very distinct, the 

 wall sloping up rather abruptly from the base towards the 

 centre. The mucro forms the middle point of the wall, 

 which incloses the orifice in front and at the sides, and 

 rises above it like a pillar. The avicularium on its inner 

 aspect is minute, and not easily detected. The ovicell is 

 large, and covers the whole of the front of the cell above 

 it ; the surface is silvery, and thickly perforated below 

 the prominent crest which crowns it. 



b. With rounded or spatulate avicularia, lateral or median. 



SCHIZOPORELLA BIAPERTA, Michelin. 

 Plate XL. figs. 7-9. 



ESCUARA BIAPERTA, Michelin, Icon. Zooph. 330, pi. Ixxix. fig. 3. 



LF.PKALIA BIAPKRTA, Busk, Crag Pol. 47, pi. vii. fig. 5: Manzoni, Bryoz. d. 



Pliocene Antico di Castrocaro, 21, pi. ii. fig. 28 *. 

 RBPTOPORIXA BIAPERTA, D'Orb. Pal. franc,. Terr. Cret. 442. 

 ESCHARELLA LiNKARis, forma BIAPERTA, Smitt, CEfv. K. Vetensk-Ak. Fcirh. 



1867, Bihang, 14 & 98, pi. mr. figs. 70, 73. 



HIPPOTIIOA BIAPKRTA, Smitt, Flor. Bryozoa, pt. ii. 46, pi. viii. figs. 173-176. 

 HIPPOTHOA DIVERGENS, id. Flor. Bryoz. pt. ii. 47, pi. ix. figs. 177, 179. 



Zocecia ovate, slightly convex, quincuncial; surface 

 smooth and shining, the front wall perforated in the 

 young state; orifice suborbicular, with a sinus, more 

 or less open, below ; peristome not raised, except in the 

 fertile cells, in which it forms a wall round the front of 

 the cell; on each side of the mouth a small, round, 



* Manzoni describes the species from the Castrocaro beds as having a 

 vibraculum on each side of the orifice, and anayicularitnu on the lower part 

 of the celL But the real nature of the lateral appendages would not be 

 apparent in fossil specimens ; and the openings left by the small, rounded 

 avicularia which occur on 8. biaperta might easily be mistaken for 

 " Tibracular pores." The avicularium on the front of the cell in Manzoni's 

 description corresponds with the large elevated avicularium, with a pointed 

 mandible, which is found on the recent specie*. 



