Dr. A. KorotnefF on Polyparium ambulans. 203 



Fiff, 5. Operculum of Porina coronata, Rss., X 85. 



Fi(j. 6. Maudible of Microporella decor ata, var. lata, MacG., X 250. 



a X 85. 

 Fig, 7. Mandible of Cribrilina monoceros, B., X 85. 

 Fig. 8. Mandible of Forina larvalis, MacG., X 85. 

 Fig. 9. Mandible of Schizoporella tuherosa (Rss.), X 85. 

 Fig. 10. Operculum of ditto, X 85. 



Fig. 11. Operculum of Rhynchopora ■profunda, MacG., X 85. 

 Fig. 12. Operculum oi Mucronella Ellerii, y&w jyorosa, H., X 85. 

 Fig. 13. Operculum of Conescharellina cancellata (B.), X 85. 

 Fig. 14. Operculum of Cellepora ovoidea {AnA.} , X 85. 

 Fig. 15. Operculum oi Hetepora fhcenicen, B., X 85. 

 Fig. 16. Mandible oi Ithynehopor a profunda, MacG., X 250. a X 85. 

 Fig. 17. Mandible of Mucronella Ellerii, var. porosa, H., X 85. 

 Fig. 18. Mandible of Conescharellina cancellata (B.), X 250. a X 85. 

 Fig. 19. Mandible of Cellepora ovoidea (And.), X 85. 

 Fig. 20. Mandible of Retepora plimnicea, X 85. 

 Fig. 21. Operculum oi Lepralia vestita, sp. nov., X 85. 

 Fig. 22. Operculum of Lepralia elimata, sp. nov., X 85. 

 Fig. 23. Mandible of Smittia Landsborovii, var., X 250. a X 85. 

 Fig. 24. Discotuhigera (?) lineata, MacG., natural size. 

 Fig. 25. Amathia biseriata, Krauss, X 16, showing radicle. 

 Fig. 26. Aviculariumand oral aperture of Conescharellina incisa (H.), X 25. 

 Fig. 27. Idmonea radians, stowing plates in the side of the ovicell, X 25. 

 Fig. 28. Plate of ditto, X 85. 

 Fig. 29. Idmonea interjuncta, MacG., X 16. 



XXI. — Polyparium ambulans, a new Goelenterate. 

 By Dr. A. Koeotnepp*. 



[Plate XIII.] 



Among the truly singular forms of animals two different types 

 are to be distinguished: — 1. The one type appears to be 

 peculiar and interesting as a transition-form between two 

 different classes of animals, and such a form is Ctenoplana 

 KowalevsMi, which I have described ; 2. The other type 

 fixes the attention of the observer in quite another respect — it 

 is an aberrant form which from various causes has separated 

 itself from its ancestors and taken up an exclusive position in 

 the animal kingdom. If at the same time the intermediate 

 forms have disappeared it only remains for the naturalist to 

 describe this form — he can hardly reckon upon giving it a 

 certain taxonoraic position. Such an exclusive aberrant 

 creature is Polyparium amhulans, of which I give the descrip- 

 tion in the following pages. 



* Extracted from an article entitled " Zwei neue Ooelenteraten," in the 

 ' Zeitschrift fiir wissenschaftliche Zoologie,' Band xlv. pp. 468-486. Prof. 

 Ehlers has put forward a different interpretation of the facts recorded by 

 the author ; a translation of his remarks will be given in a future number 

 of this iournal, 



14* 



