80 BRACHIOPODA. 



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

 Avicularia, vibracula, and ovicells are often present. 



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

 several rows. Cellnlaria Pallas, C. Peachii Busk, Scrupocellarla Van Ben. 

 S. scruposa L. 



Fam. Bicellariidae. Zocecia 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. avidularia L. (fig. 547). 



Fam. Membraniporidae. Zooecia more calcified and united to form an in 

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

 pertusa Esp., Adriatic ; Flustra membranacea L. 



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

 Retepora Lam., M. cellulosa L., Mediterranean to the Arctic Ocean. 



L 



Ar ^g^*^Jb^3%S5sL^ Tr 



It 



lice. 

 McL 



FIG. 554. Anatomy of Waldheimia australis, seen from the side (after Hancock) Do, Dorsal 

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

 Ar, arms : Via, anterior body wall ; Oe, oesophagus ; I), intestine ending blindly : 0, point 

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



Class II. BRACHIOPODA.* 



Fixed Molluscoidea, with anterior (dorsal) and posterior (ventral) 

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



The more recent researches into the development have shown that 



* E. 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 of the British fossil Brachiopoda." 1858. 



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

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



Kowalevski, " Eussische Abhandluner iiber Brachiopoden-Entwickelung." 

 Moskau, 1874. 



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

 the Brachiopoda." Chesapeake Zool. Lai. Sclent. Results. 187 



