352 



MOLLUSCOIDEA— BRYOZOA 



PHYLUM V 



with oral spines. Usually one senii-lunate or circular pore lieneatli the orifice, 

 occasionally two or three. Tertiary and Recent. 



Family 11. Porinidae d'Orbigny. 



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

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



Poriiia d'Orl). Zoaria consisting of flattened or sub-cylindrical branches, celluli- 

 ferous on both sides, or encrusting. With age the spaces between the raised apertures 

 become filled with a porous calcareous dej^osit. Avicularia and ooecia occasionally 



distinguishable. 



Cretaceous to Recent. 



Family 12. Smittinidae Levinseu. 



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

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



Smittina Norman (Smittia 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 Ijeneath the sinus. Cretaceous to Recent. 



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

 and the low-er jiart of the peristome elevated into a more or 

 less prominent mucro. Cretaceous to Recent. 



Porella Gray. Zoaria encrusting or erect. Zooecia with a 



Fig. 520. 



Mucronella coccinm 

 Abildg. Miocene ; Eisen- 

 .stadt, Haiij;ury. Anuiii- 

 ber of zoojcia enlarged 

 (after Reuss). The aper- 

 tures are denticulated, 

 and each zoiecium has a 

 pair of avicularia. o, 

 Ovicell. 



Fio. 521. 



Lepralia pallusiana Moll. 

 Recent ; England. Zowcia 

 highly inagnitied (after 

 Hinciss). 



ScMzo porella corituta 

 (G. and H.). Po.st- 

 I'liocene ; Santa Bar- 

 bara Co. , Cal. Zooecia 

 highly magnified 



(after Gabb and 

 Horn). 



semicircular pi'iinary orifice; tlie secondaiy (adult) orifice elongate, inversely sub- 

 triangular, or liorseshoe-shaped, and enclosing an aviculaiium witli a rounded or 



Cretaceous to Recent. 



sub-triangular mandible 



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 simj)le 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. 



Hipipoporina Neviaui. Like Lepralia luit aperture constricted l)y two lateral 

 teeth. Tertiary. 



Hchizoporella Hincks (Fig. 522). Zoaiia variable ; /.ucjocial oi'ifice varying from 



