CHESTER — STKUCTURE OF PSEUDOPLEXAUR.V CRASSA. 730 



licM tlic incso^loi'jil lu'twork of colls to 1)0 neuro-pluigooytic in func- 

 tion. My feeding' with colored iiiiitcrijil, slio prov(>(l the inj^'cstioTi uiid 

 the carriiij^c of such nuitcrial hy the auioehoid niovcnieuts of th(; 

 iucso,<,doe;d cells. Kassiaiiow (:08) reviewed the litcnitun! for the 

 uuisele and iuM-\e systems in Alcyonuria dij,ntiituin, studied these 

 systems ami described in detail the cells of the ectoderm, endoderm 

 and niesoj,doea with reference to tliem. He denied a nervous function 

 for the neuro-incso.i;Iocal cells of Pratt. 



Auioni;- the IVmiatulacea, studies have been made by Korotnetf ('87) 

 and by Bujor (.01) on ^'eretillum. They described the cells of the 

 ectoderm and endoderm carefully. 



The only complete study of the cell structure of representatives 

 of the fjrftup Gornonacea is by von Koch ('87), who made a compara- 

 ti\e study of the structure and minute anatomy of the forms found in 

 the Bay of Naples, giving most attention to Unicella (Gorgonia) 

 cavolinii. 



Wilson ('84) studied the mesenterial filaments of a number of 

 species representing the three groups. He described the difference 

 in structure of the ventral and dorsal mesenterial filaments and the 

 origin of each from diflerent germ layers. 



Bourne ('99), in a paper giving the result of his study of the origin 

 of the skeleton in Anthozoa, describes the origin and minute struc- 

 ture of the alc\onarian spicule and the structure of the massive 

 skeleton of the alcyonarian Heliopora. He further studied the struc- 

 ture and origin of "holdfasts," or desmocytes, in Heliopora, as well 

 as in matlreporarian forms. 



Woodland (:05) reviewed the literature on the origin of the alcyon- 

 arian spicule and made a very complete study of it for Alcyonium. 

 The names of von Koch ('78, '82*^), Studer "('87, :06), and Alfred 

 Schneifler (:05) are important in the history of researches on the 

 origin of the horny skeleton. Kinoshita (:10) has seen the origin of 

 axis epithelium in young forms of Anthoplexaura and has confirmed 

 von Koch's account of its ectodermal origin in the young form. 



The study of this gorgonian coral (Pseudoplexaura crassa) was 

 pursued during the summers of 1909 and 1910 at the Bermuda Bio- 

 logical Station for Research, and during the winter of 1909-1910 at 

 the Zoological Laboratory of Harvard University. I wish to express 

 my great indebtedness to Dr. E. L. Mark, the Director of these 

 Laboratories for guidance and generous assistance. 



