ANATOMY 



469 



characteristic yellowish pigment. The stomach gives off the 

 intestine (m), which is lined by strong cilia, by means of which 

 a rotatory movement is given to the faeces contained in it. This 



FIG. 234. Alcyonidium albidum Alder, Banyuls-snr-Mer. Diagram showing the struc- 

 ture of a single zooecium with its polypide retracted : a, anus ; d, diaphragm ; e, 

 ectocyst ; e///, ectoderm ; /, funiculns ; //, ganglion ; /, iiitt-rtentacular organ ; in, 

 intestine ; m, mouth ; mm, mesoderm of body-wall ; o, orifice ; of, oesophagus ; or. 

 ovary ; p, parietal muscles ; ph, pharynx ; p.r, parieto-Viiginal muscles ; r, rectum ; 

 r.in, retractor muscles (contracted) ; ,s-, stomach ; t, testis ; tn, tentacles ; t.s, ten- 

 tacle-sheath or kaniptoderm. (After Prouho. 1 ) 



communicates by a narrow passage with the rectum (/), which 

 opens by means of the anus (). 



Tn the retracted condition the tentacles (/.) lie in a cavity 



1 An-h. Zool. X.r/1. '2 st-r. x. 1892. 



