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 ; zooscia in two or 

 several rows. CMularia Pallas, C. Peacliii Busk, SenqwceUaria Van Ben. 

 S. scrtiposa 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. Bitf/ula Oken, B. aricularia L. (fig. 547). 



Fam. Membraniporidse. Zooecia more calcified and united to form an in- 

 crusting colony. Membranipora Blainv., M. pilosa L., Adriatic ; LcjiTiil'ui 

 pertusa Esp., Adriatic ; Flmtra memlranticca L. 



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

 Jteti'pora Lam., 7?. ccllulosa L., Mediterranean to the Arctic Ocean. 



T 



St 



cc 



Te Oe 



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

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

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

 of opening of the liver (Z) ; 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 



* R. Owen. " On the anatomy of the Brachiopoda." Transact. Zool. &'oc., 

 London, 1835. 



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

 don, 1858. 



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



Lacaze-Duthiers, ''Histoire naturelle des Brachiopodes vivants de la Mediter- 

 ranee." Ann. des. Sc. A'at., 1871, Tom. XV. 



Kowalevski, " Eussische Abhandlung iiber Brachiopodeii-Entwickelung." 

 Moskau, 1874. 



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

 the Brachiopoda," Cht'*aj>eafte Zool. Lab. Sclent. Results. 1878. 



