EXPLANATION OF PLATES. 



All of the figures in the plates were drawn by Miss Lilian Hulsebns. Where figures have been copied from the 

 works of other authors, the source is indicated. Nearly all of the figures copied from Allman, Clarke, and Fewkes 

 are from publications of the Museum of Comparative Zoology, Cambridge, Massachusetts, by permission of Doctor 

 Alexander Agassiz. 



In all cases where no other source is indicated, the figures were drawn by Miss Hulsebus from camera lucida 

 sketches from nature by Professor C. C. Nutting. 



All of the figures in the text were drawn by Miss Mary Macbrlde. Unless otherwise indicated, they are after 

 camera lucida sketches by Professor C. C. Nutting. 



PLATE I. 



FIG. 1. Plumularia setacea Ellis. Portion of colony with gonangia (enlarged). 

 la. Plumularia setacea. Young gonaugium (enlarged). 



2. Plumularia setacea. Hydrotheca and hydranth (greatly enlarged). 



3. Plumularia setacea. Part of a hydrocladium (enlarged). 



4. Plumularia setacea. Portion of same (greatly enlarged). 



5. Plumularia meyalocephala Allinan (enlarged). (After Allmau.) 



6. Plumularia oligopyxis Kirchenpauer (enlarged). (After Kirchenpauer.) 



7. Plumularia oligopyxie. Hydrotheca (greatly enlarged). (After Kirchenpauer.) 



PLATE II. 

 FIG. 1. Plumularia altitlieca Nutting (enlarged). 



2. Plumularia filicula Allman (enlarged). (After Allrnan.) 



3. Plumularia hellcri Hindis (enlarged). (After Marktauner-Turneretscher.) 



4. Plumularia floridana Nutting (enlarged). 



5. Plumularia Joritlana. Portion of hydrocladium (greatly enlarged). 



6. Plumularia ftlicaulis Kircheupauer. Portion of hydrocladium (enlarged). (After Bale.) 



PLATE III. 



FIG. 1. Plumularia catliariiin Hincks. Portion of a hydrocladium (enlarged). (After Hiucks.) 



2. Plumularia caiharina. Gonaugium (enlarged). (After Hincks.) 



3. Plumularia geminata Allmau (enlarged). (After Allman.) 



4. Plumularia geminata. Portion of a hydrocladium (greatly enlarged). (After Allman.) 



5. Plumularia clarkei Nutting (enlarged). 



. PLATE IV. 

 FIG. 1. Plumularia alternata Nutting (enlarged). 



2. Plumularia alternata. Portion of hydrocladinm (greatly enlarged). 



3. Plumularia plumularoides (Clark) (greatly enlarged). (After Clark.) 



4. Schizotricha tenella (Verrill) (greatly enlarged). 



5. Schizotricha tenellu. Portion of hydrocladium (greatly enlarged). 



PLATE V. 

 FIG. 1. Plumularia inermis Nutting (enlarged). 



2. Plumularia inermis. Hydrotheca and hydranth (greatly enlarged). 

 2. Plumularia inermis. Hydrotheca (greatly enlarged. 



3. Plumularia caulitlieca Fewkes. Portion of stem (enlarged). 



4. Plumularia caulitlieca. Portion of hydrocladium (enlarged). 



5. Plumularia caulitheca. Hydrothecal iuternode (greatly enlarged). 



6. Plitmularia attenuata Allmau (enlarged). (After Allman.) 



PLATE VI. 

 FIG. 1. Plumularia corrugata Nutting (enlarged). 



2. Plumularia corrugata. Portion of hydrocladium (greatly enlarged). 



3. Plumularia corrugata. Part of colony, showing gouangia (enlarged). 



4. Plumularia palmeri Nutting. Portion of hydrocladium (enlarged). 



5. Plumularia palmeri. Hydrocladial internode (greatly enlarged). 



6. Plumularia lagenifera Allmau. Hydrocladial interuode (enlarged). 

 . Plumularia lagenifera. Portion of stem aud a hydrocladinin. 



8. Plumularia laijenifera. Gonangia. 



9. Plumularia lagenifera Allmau. Part of colony with gonangium. (After Allman.) 

 10. Plumularia lagcnifera. Part of a hydrocladium. (After Allmau.) 



