AMATHIA. 515 



stem it bifurcates. The zocecia, which are pretty regu- 

 larly ovate in form, and so transparent as to keep no 

 secrets, are unilateral, and ranged in single file, dimi- 

 nishing gradually in size towards the end of the branch- 

 lets. The polypide is furnished with short stiff tentacles, 

 destitute of the tactile setae which occur in Bowerbankia 

 imbricata and other forms. 



Genus AMATHIA, Lamouroux. 



Der. From Amathia, one of the Nereids, according to Homer. 



AMATHIA, Lamouroui (1812): D'Orbigny (for species with the cells in con- 

 tinuous series). 



SERTVLARIA (part.), Linnaeus : &c. 



SEKIALARIA, Lamarck (1816) : Fleming : Johnst. : D'Orbigny (for species 

 with the cells in distinct groups) : &c. 



VALKERIA (part.), Dalyell. 



AMATHELLA (sp.), CHARADELLA (p.), &c., Gray. 



GENERIC CHARACTER. ZOARIUM consisting of a creeping 

 tubular stem and erect filiform shoots, dichotomously 

 branched. ZOCECIA subtubular, in two parallel rows, dis- 

 posed in distinct groups, which are placed on one or both 

 sides of the stem, or wind spirally round it ; or forming a 

 continuous series. 



D'ORBIGNV has placed the species with the cells in 

 groups and those with the cells in continuous series in 

 two separate genera, applying Lamouroux's name to one 

 and Lamarck's to the other. But the distinction is purely 

 artificial ; the structural difference between the two sec- 

 tions is quite unimportant, and they arc united by inter- 

 mediate forms. The species like our own A. lendigera, 

 with the cells in distinct unilateral groups, are connected 

 through such forms as A. alternata, Lamx., in which the 

 groups are placed alternately on opposite sides, with 



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