538 ON Tin: BRANCHING-SYSTEMS OF THE ALCYONACEA. 



Fig. 20. Transverse section of a branchlet borne on the branch of whieli a section is represented in 



fig. 19. X 60. a., A young- authocodia. 

 Fig. 21. Transverse section of the lower end of the storaodceum of L. nitlda, showing the uniform lining 



of columnar ciliated epithelium, mes., Mesenteries ; t:n., endoderm. Zeiss' ^ Horn. Innn. 



Comp. Oc. 4. 

 Pig. 22. Transverse section through a soicuiium of Leiiiaulia nitida in which a zooid is beginning to be 



formed, X 4)20. ec. Ectoderm ; ew., endoderm ; m^., mesogloea; so/., solenia ; s/., thickening 



of ectoderm forming the primordium of the stomodasuiu ; sch., scleroblasts budding off from 



the ectoderm; s.sh., spicule-slieath. 

 Fig. 23. Vertical section through another zooid bud, showing the formation of the mesenteries, mes,. 



Mesenteries ; zx., a zoo.xanthella enclosed in a cell. Other lettering as in fig. 22. Zeiss' ^.^ 



Horn. Imm. Oc. 2. 

 Fig. 2-1. Vertical section through an older zooid bud. st.', Non-ciliated upper, and st.", ciliated lower 



regions of the stomodteuni ; mg.' . mesogloea in course of formation between ectoderm-cells. 



Other lettering as before. Zeiss' jV Horn. luim. Oc. 2. 



