348 



MOLLUSCOIDEA— BRYOZOA 



PHYLUM V 



demoiistrated tlie inucli greater importance of zocccial cliaracters, a decided advance 

 was made, Levinsen's stiidies lipon tlie recent Clieilostoiiiata liave resiüted in a 

 splendid, detailed Classification which nnfortunately depends upon cliaracters making 

 it difRcult of application to the fossil forms. Only brief descriptions of tlie more 

 iinportant genera, or those liaving niimerous fossil representatives, can be introduced 

 liere. 



Suborder A. ANASCA Levinsen. 



Gompensation sac wanting ; frontal löall membraneous or calcareoiis, d&pressed and 

 surrounded by raised margins ; opercular and subopercular areas not separated by a 

 calcareous bar. 



Family 1. Aeteidae Hincks. 



Zoarium miilinear, adnate ; zooßcia partially erect^ with membraneous apertures. 

 Aetea Lam. Tertiary and Recent ; Europe. 



Family 2. Eucrateidae Hincks. 



Zoaria branching, erect and free, or recumbent. Zooecia uniserial or biserial, 

 pyriform, with a sub-terminal and usually oblique aperture. Avicularian and 



vibracular appendages ivanting. Cre- 

 taceous to Recent. 



Eucratea Lamx. (Fig. 508). 



Zoaria entirely deciimbent, or com- 



posed of a creeping adlierent base 



and erect braiicliing slioots. Zooecia 



calcareous or siib-calcareoiis, rising 



oiie from anotlier so as to form 



Single series. Brauches springing 



froin tlie front of a zooeciiim Ijelow 



Fig. 508. the aperture. Cretaceoiis to Recent. 



Eucratea lahmta (Novak). Cenomanian ; Velim, Bohemia. Gemellaria Savigliy ; Notamia 



A, Zoarium, i/^. B, Zooecia, tliree of them with fractured -^^^ • m x- i -d + 



waiis, highiy magnified (after Novak). Fleming, lei'tiary aiid Recent. 



Family 3. Scrupocellariidae Biisk. 



Zoarium erect, usually jointed, dichotomously branching, phytoid. Zooecia in two 

 or more series, closely united and arranged in the same plane. Sessile avicularia and 

 vibracula generally present. Tertiary and Recent. 



Menipea, Caberea Lamx. ; Scrupocellaria Van Beiied. Eocene and Recent. 



Family 4. Oellulariidae Levinsen. {Salicornariadae Biisk). 



Zoarium erect, sub-cylindrical, dichotomously branching, usually jointed. Zooicia 

 rhomboidal or hexagonal, each corresponding to an area, and disposed in series about an 

 imaginary axis. Front depressed, usually concave. Orifice crescentic or semicircular, 

 situated slightly above the centre of the cell. Ocecia inconspicuous, opening at or near 

 the summit of the area above the orifice. Avicularia usually present. Cretaceoiis to 

 Recent. 



Gellularia Pallas {Cellaria Lam,; Salicornaria Cuv.) (Fig. 509). Zoarium jointed. 



