124 SECTION A. GENERAL ZOOLOGY. 



SECTION A. GENERAL ZOOLOGY. 



Wednesday, 24 August, at the Guildhall at 2 p.m. 

 C/iainna?i, Prof. Milne-Edwards. 



Prof. Haeckel developed the principles of modern phylogenetic 

 classification which he had first enunciated in his " General Mor- 

 phology" and most recently in his "Systematic Phylogeny" (1896). 

 He brought forward arguments in favour of the complementary 

 value of the three great " Phyletic Archives," Palaeontology, Com- 

 parative Anatomy and Ontogeny. He proceeded to explain the 

 modern pedigree of the Animal Kingdom and the relations of the 

 10 or 12 phyla to the lower Ccelenteria, and the higher Coelomaria 

 as the two main groups of the Metazoa. 



The following were recognised as true phyla (i.e. monophyletic 

 groups, each arising from a common stem) ; Vertebrates, Tunicates, 

 EcJiinoderms, Molluscs (all derived from Vermalia which in turn 

 were derived from Platodes), Cnidaria and SpoJigicE, the two last 

 named being below and independent of the others. 



The unity of the Articulata (= Arthropoda and Annelida) was 

 much debated. The group might be considered to comprise three 

 sub-phyla, the Crustacea and Tracheata arising from two different 

 groups of the Annelida. These again have originated from Verm- 

 alia, i.e. the so-called "Vermes" after removal of the Annelids and 

 Platoda. P'our groups of Vermalia were distinguished, Prosopygia, 

 Frontonia and Strongylaria — all three developed from Rotatoria 

 (Trochophora). 



Prof. Marcus Hartog (Cork) rejected the view that the 

 Rotatoria are to be placed at the base of the Annelids — the view 

 being founded mainly on the resemblance between the trochophore 

 larva and the female of the pelagic Rotifer Trockosphaera, an 

 extremely modified form. 



Prof. L. V. Graff (Graz) explained his map showing the 

 Geographical Distribution of the Land-planarians and exhibited 

 the plates of his monograph of this group. 



Mr G. C. Bourne gave an account of the formation and struc- 

 ture of the calcareous skeleton in Anthozoa, showing that in the 

 case of the spicules of Alcj'onarians there is a matrix of organic 

 threads upon which the calcareous structure is moulded, and that 

 in the case of Heliopora and the Madreporaria the corallum is not 



