350 



MOLLUSCOIDEA— BRYOZOA 



PHYLUM V 



immersed, their borders elevated. Orifice rounded or semi-elliftical, situated more or less 

 in advance of the depressed front. Small vibracidar cells usually p-esent. Cretaceous 

 to Recent. 



Lunulites Lamx. (Fig. 512). Zooecia arranged in series radiating from the 

 centre and bifurcating as they advance toward the border. Vibracular cells usually 

 elongate, lying in linear series between the rows of zooecia. Very abundant in the 

 Upper Cretaceous and Tertiary ; also Recent. 



Stichopora Hagw. emend. Busk. Vibracular cells wanting. Zooecia equal, 



hexagonal, not arranged in radiating series. 

 Cretaceous. 



Selenaria Busk. Cretaceous to Recent. 







■-c> 



■^fc^^^ii^^ 



Pig. 513. 



Membraniporella 

 ahhotU (G. and H.). 

 Cretaceous ; N.J. 

 Zocecia highly mag- 

 nified (after Gabb 

 and Horn). 



PlQ. 514. 



Cribrilina liecrmanni 

 (G. and H.). Post-Plio- 

 cene ; Santa Barbara 

 Co., Cal. Zooecia highly 

 magnified (after Gabb 

 and Horn). 



Family 7. Oribrilinidae Hincks. 



Zoaria encrusting or erect. Zooecia having 

 the front wall more or less fissured, or traversed 

 by radiating furrows. Cretaceous to Recent. 



Membraniporella Smitt (Fig. 5 1 3). Zoaria 

 encrusting or rising into free foliaceous ex- 

 pansions, sometimes consisting of superim- 

 posed layers. Zocecia closed in front by a 

 number of flattened calcareous ribs more or less consolidated centrally. Cretaceous 

 to Recent. 



Cribrilina Gray (Fig. 514). Zoaria usually encrusting. Zooecia having the 

 front more or less occupied by radiating or transverse rows of punctures, each row in 

 a furrow ; orifice semicircular or sub-orbicular. Cretaceous to Recent. 



Family 8. Onychocellidae Jullien (emend.). 



Zoaria encrusting or erect, ramose, continuous, the branches more or less compressed 

 and bilaminar ; surface areolated. Zoxcia usually hexagonal, their margins raised, 

 the front not entirely calci- 

 fied. Opesial aperture of 

 moderate size, generally semi- 

 elliptical, sometimes spread- 

 ing below, in other cases sub- 

 circular. Oral opening 

 small, usually crescentic or 

 semicircular. Ocecia in- 

 conspicuous ; intercalated 

 vicarious avicularia gener- 

 ally present ; special pores 

 'Wanting. Jurassic to Re- 

 cent ; chiefly Cretaceous. 



Pig. 515. 



Onychocella angii- 

 ?osa (Reuss). Upper 

 Eocene ; Nortliern 

 ,^ Italy. Surface, 20/j 



Mem- (after Waters). 



Pig. 516. 



Vincidaria virgo Hagw. Upper Cretaceous ; 

 Riigen. a, Portion of zoarium, i/j. h. Cross- 

 section, c, Vertical section, enlarged. 



Onychocella Jullien (^s- 

 chara, Flustrellaria, p.p. 

 d'Orb. ; Cellepora, 

 branipora, Vincularia, etc 

 auct.) (Figs. 515, 516). Zoaria encrusting or erect. Oral opening semicircular or 

 crescentic." Avicularian openings simple, oval ; the area in wliich they are situated 

 drawn out above. Jura of Normandy, and Cretaceous to Recent. 



