80 BBACHIOPODA. 



cells can be closed by a movable operculum or by a sphincter muscle. 

 Avicularia, vibracula, and ovicells are often present. 



Fam. Cellularildae. Dichotomously branched colonies ; zooecia in two or 

 several rows. Cellvlaria Pallas, C. Peachii Busk, Scrupocdlaria Van Ben. 

 S. scruposa L. 



Fam. Bicellariidae. Zooecia conical or quadrangular, bent. Lateral face on 

 which the aperture is placed is elliptical, and placed obliquely to the median 

 plane of the axis. Bugula Oken, B. avieularia L. (fig. 547). 



Fam. Membraniporidse. Zocecia more calcified and united to form an in 

 crusting colony. Meiribranipora Blainv., M. pilosa L., Adriatic ; Lepralia 

 pertusa Esp., Adriatic ; Flustra membranacea L. 



Fam. Beteporidae. Zooecia oval-cylindrical, united to a reticulated colony. 

 Itetepora Lam., R. odlulosa L., Mediterranean to the Arctic Ocean. 



/- r^-p^re-.' L 



Ar 



Ml 



Ye O' e 



TIG. 554. Anatomy of Waldheimia australis, seen from the side (after Hancock) Do, Dors.il 

 side; Ve, ventral side of the mantle; St, peduncle; Ma, adductor; Md, divaricator 

 Ar, arms : Vic, anterior body wall ; Oe, oesophagus ; D, intestine ending blindly : 0, point 

 of opening of the liver (L); Tr, funnel of the oviduct. 



Class II. BRACHIOPODA.* 



Fixed Mottuscoidea, ivith anterior (dorsal) and posterior (ventral] 

 shell-valves, with two spirally-coiled buccal arms. 



The more recent researches into the development have shown that 



* R. Owen, " On the anatomy of the Brachiopoda." Transact. Zool. Soc.. 

 London, 1835. 



A. Hancock, " On the organisation of the Brachiopoda." Phil. Trans., Lon- 

 don, 1858. 



Davidson, " Monograph cf the British fossil Brachiopoda." 1858. 



Lacaze-Duthiers. " Histoire naturelle des Brachiopodes vivants de la Mediter- 

 ranee." Ann. des. So. Nat., 1871, Tom. XV. 



Kowalevski, " Eussische Abhandlune: uber Brachiopoden-Entwickelung." 

 Moskau, 1874. 



W. K. Brooks, " The development of Lingula, and the systematic position of 

 the Brachiopoda," Chesapeake Zool. Lab. Sclent. Results; 1878. 



