320 



MOLLUSCOIDEA— BRYOZOA 



PHYLÜM V 



zocßcia grown back to back. Very abundant in the Jura, less common in Cretaceous 

 and Tertiaiy. 



Bidiastopora d'Orb. Like Diastopora, but the zoaria forming only narrow, parallel- 

 edged brancbes. Cretaceous. 



ReptomuUisparsa, Cellulipora and Filicrisina d'Orb. Cretaceous. 



Diastoporina Ulrich. Ordovician. Heder ella and Hernodia Hall ; and Reptaria 

 Rolle. Devonian. 



Family 3. Idmoneidae Busk. 



Zoaria forming free or adnate, variously compressed hranches. Zocßcial apertures 

 rounded, more or less elevated, usually arranged in transverse rows on two faces of the 

 hranches ; sometimes the two faces are confluent. Dorsal surface of the hranches without 

 zooecia, hut often occupied hy numerous small tubulär pores, which may also occur near 

 the apertures. Sac-like ovicells with hut a single opening. Ordovician to Recent. 



Idmonea Lamx. Zoarium adnate with apertures opening in transverse series. 

 Jurassic to Recent. 



Grisina d'Orb. (Fig. 442). Zoarium erect, simple or branching. Brauches 

 usually triangulär, two of the faces carrying the zooecial apertures, which are generally 

 arranged in alternating transverse series. Jurassic to Recent. 



Bisidmonea d'Orb. Quadrate, 

 simple or branching stems, bear- 

 ing zooecial apertures on all faces. 

 Cretaceous, 



Retecava d'Orb. Zoaria reti- 

 culated ; branches greatly com- 

 pressed laterally ; reverse side 

 occupied by an axial rod. Cre- 

 taceous. 



Bicrisina, Bituhigera, Repto- 

 fascigera, Semiclausa, Sulcocava 

 {Laterocava) d'Orb. ; and Pergen- 

 sella Gregory. Cretaceous. 



Phalangella Gray. Creta- 

 ceous to Recent. 



Protocrisina Ulr. (Fig. 443). 

 Narrow, bifurcating branches, celluliferous on one side only. Zocecia sub- tubulär, 

 with prominent circular apertures arranged in intersecting diagonal series. Small 

 pores, apparently communicating with interior of the zocecia, irregularly distributed 

 over both faces of the branches. Ordovician and Silurian. 



Fig. 442. 



Grisina dorsata Hagenow, 

 Cretaceous; Maastricht. J, Brauch, nat. 

 size. B, Upper, and C, Lower side, highly 

 magnifled. 



Uppermost 



Fig. 443. 



Protocrisina exigua 

 Ulrich. Trenton 

 Group; Trenton, 

 N.Y. Branches of a 

 large expansion, i^^/i. 



Family 4. Entalophoridae Reuss. 



Zoaria ramöse ; hranches free, suh-cylindrical, with 

 rounded and more or less prominently exserted zooecial 

 apertures opening on all sides. (?) Without accessory or 

 interstitial pores of any kind. Ordovician to Recent, 



Entalophora Lamx. {Glavisparsa d'Orb. ; Pergensia 

 Walford) (Fig. 444). Zooecial tubes disposed about an 

 imaginary axis, and with rounded, more or less prom- 

 inent apertures. Jurassic to Recent. 



Spiropora Lamx. (Pustulopora and Gricopora Blain- 

 ville) (Fig. 445). Like the preceding, but apertures Plauen ,^SaxJny 



Fig. 444. 



Entalophora vir- 

 gula Hagenow. 

 Plänerkalk; 



Fig. 445. 



Spiropora vcr- 

 ticillata Goldf. 

 Upper Cretace- 

 ous ; Maestricht 

 (after Hagenow). 



