222 



W. G. RIDEVVOOD. 



loplius,! and that the last plumes do uot develop between 

 the earlier plumes and the buccal shield, as recorded by the 

 same writer, but on the side of those plumes remote from the 

 buccal shield. His figures 04 — 08 are reproduced as text- 



fig. 1. 



I was unable to settle the point satisfactorily in time for 

 the introduction of my results into the two papers describing 

 the structure of the polypides and tubaria of the new species,^ 

 but since the completion of those papers I have made an 

 exhaustive study of the growth of the plumes in buds of 





''or ^ 





65 



— "II U ill 



^ ^(# ^ OS) ^^ 



67. 



m n I I n m 



68 



Text-figuue 1. — Diagrammatic transverse sections of plumes and 

 buccal sliield of Ceplialodiscus dodccaloplius at five stages of 

 development. Cojiied from A. T. Maslerman's jiaper in the 'Trans. 

 Roy. Soc. Edin.,' vol. xxxix, part 3, 1S98, plate i, figs. 64 — OS. 

 The original numbering has been retained. 



Cephalodiscus hodgsoni, C. nigresceus, and C. gil- 

 christi, and having made from the abundant material at 

 my disposal a well-graded series of buds of each species, 1 

 was enabled to confirm my earlier conclusions. 



I finally prepared a series of buds of the " Challenger " 

 species, Cephalodiscus dodecalophus, with the result 

 that I am satisfied that the buds of this species agree with 



' 'Trans. Roy. Soc. Edin.,' vol. xxxix, part 3, 189S, p. 521. 

 ' '"Discovery" Expedition Rcjjorts,' vol. ii, l'J07, and 'Marine Investi- 

 gations in South Africa,' vol. iv, I'JOfl. 



