352 



MOLLUSCOIDEA— BRYOZOA 



PHYLÜM V 



with oral spiiies, Usually one seini-lunate or circular pore beneatli tlie orifice, 

 occasionally two or tliree. Tertiary and Recent. 



Family 11. Porinidae d'Orbigny. 



Zoaria encrusting, or erect and ramified. Zooßcia with a raised tubulär or sub-tubular 

 orifice, and frequently with a special pore on the front wall. Cretaceous to Recent. 



Porina d'Orb. Zoaria consisting of flattened or snb-cylindrical branclies, celluli- 

 ferous on botli sides, or encrusting. Witli age tlie sj)aces between the raised apertures 

 becoine filled with a porous calcareous deposit. Avicularia and oa3cia occasionally 

 distinguishable. Cretaceous to Recent. 



Family 12. Smittinidae Levinsen. 



For this and the next foUowing family only provisional diagnoses can be given at 

 the present time, and for that reason none is attempted here. 



Smittina Norman (ßmittia Hincks). Zoaria encrusting, or erect and foliaceous. 

 Primary orifice of zooecia sub-orbicular, the lower margin with an internal median 

 denticle. Secondary orifice canaliculate below ; generally a small avicularium either 

 within or just beneath the sinus. Cretaceous to Recent. 



Mucronella Hincks (Fig. 520). Similar to Smittina, but with simpler orifice, 

 and the lower part of the peristome elevated into a more or 

 less prominent mucro. Cretaceous to Recent. 



Porella Gray. Zoaria encrusting or erect. Zocecia with a 



Fig. 520. 



Mticronella coccinea 

 Abildg. Miocene ; Eisen- 

 stadt, Hungary. Anuiii- 

 ber of zooecia enlarged 

 (after Renss). The aper- 

 tures are denticulated, 

 and each zooecium has a 

 pair of avicularia. o, 

 Ovicell. 



Fig. 521. 



Lepralia pallasiana Moll. 

 Recent ; England. Zocecia 

 highly magnitied (after 

 Hincks). 



Fi(}. 522. 



Schizoporella cornuta 

 (G. and H.). Post- 

 Pliocene ; Santa Bar- 

 bara Co., Cal. Zooecia 

 highly magnified 



(after Gabb and 

 Hörn). 



semicircular primary orifice; the secondary (adult) orifice elongate, inversely sub- 

 triangular, or horseshoe-shaped, and enclosing an avicularium with a rounded or 

 sub-triangular mandible. Cretaceous to Recent. 



Family 13. Lepraliidae Smitt. 



This family, like the preceding one, can be only provisionally defined at present. 



Lepralia Johnson (Fig. 521). Zoaria encrusting or rising into simple or branching 

 expansions, composed of one or two layers of cells. Zooecia usually ovate, the orifice 

 with a thin peristome and entire lower margin. Rare in Cretaceous, more abundant 

 in Tertiary and Recent. 



Hippoporina Neviani. Like Lepralia but aperture constricted ])y two lateral 

 teeth. Tertiary. 



Schizoporella Hincks (Fig. 522). Zoaria variable : zooccial oiifice varying from 



