PLUMES OP CEPHALODISCUS. 231 



no larger in proportion than in C. hodgsoni (cf. text-fig. 

 2, G). 



In J the fourth plumes are appearing, and the gradation 

 from the first plumes to the fourth is fairly uniform; refrac- 

 tive beads are now visible on the second plumes. On 



Text-figure 4. — Ceplialodiscus dodecalophus. Fijjures 

 illustrating the development of the plumes of the buds. J, K and 

 L are ventral views of the collar and appendages (plumes and 

 post-oral lamella) ; B and F are side views of complete buds ; the 

 remaining figures are dorsal views of complete buds. The first pair 

 of plumes are just appearing in B and C, the second are fairly large 

 in E, the third are appearing in F and G, and the fourth in J ; in K 

 the fourth plumes are moderately well developed, but there are no 

 fifth plumes ; in L the fifth plumes are fairly well developed. All 

 figures enlarged 62 diameters. For explanation of the lettering see 

 end of paper. 



comparing j of text-fig. 4 with J of text-fig. 2 it will be seen 

 that in C. dodecalophus the lateral lobes of the post- 



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