PROCEEDINGS OF SECTION C. 437 



partitions constituting the septa. At a later stage the cells become 

 parallel -sided, and the pseudo -septate structure is characteristic of 

 the older growth. 



As Man is in some respects intermediate between the Orang and 

 the Chimpanzee — a study of their common features leading one to a 

 knowledge of the primeval Pithecanthropus — may not the Archseo- 

 cyathinae be descendants of that Proto-coelenterate from which also 

 are derived the sponges and corals ? One can at all events hope for 

 much for evolution from these fossils — by far the most elaborate and 

 best preserved relics of the lower invertebrata from the oldest horizons 

 of the Age of Life. 



SUIVIMARY. 

 Evidence tends to show that the Archseocyathinse were compound 

 organisms, whose internal structure — both as regard composition and 

 regularity — -approximates to that of the Anthozoa, but whose general 

 shape, protean forms, and methods of attachment are distinct from the 

 Coelenterates and resemble the Porifera. In conclusion it may be 

 suggested that in this family we have a division of the Metazoa of equal 

 rank with the Porifera and Coelenterata, and possibly representing a 

 missing link between these two phyla. 



KEY TO PLATES. 



Plate I., fig. 1. — Longitudinal section (strongly etched) of turbinate 

 Archseocyathinoid, showing very clearly the outer and inner walls, 

 septa, and tabulse,. 28 mm. long. 



Plate I., fig. 2. — Cross sections (strongly etched) of turbinate 

 Archgeocyathinoids showing tabulse (on the left) and exothecal lamellae 

 (on the right). 



Plate II., fig. 1 — Specimen of bell-shaped calice, showing outer 

 wall, septa, and expanded rim. (See also fig. 6.) 



Plate II., fig. 2.— Vertical section through flabellate type, showing 

 cylindrical rhizoid bundles attached to lower wall. (See also figs. 

 7 and 8.) 



