cxxxviii BRITISH GRAPTOLITES. 



the place of the modern Hydrozoa, and are perhaps phylogenetically related 

 to them." 



C. The Position of the Gfraptolites in the Zoological System.— The Axonophora 

 and Axonolipa are very distinct, the only point of similarity between them being 

 the form of the sicnla. He discusses at great length the relationship of the 

 Graptolites to the Sertularians, but thinks that all the resemblances are superficial. 

 Between the Dendrograptidi and living Plumularians, however, there is much direct 

 relationship in the organisation of the grown animal, and the only main distinction 

 between them is the want of a common canal in the former, and the shape of the 

 embryonic polyps. 



D. Classification. — The classification adopted by Freeh differs in many respects 

 from that proposed by British and Swedish workers, and the number of genera 

 and species, are, in the majority of cases, materially decreased. His classification 

 is as follows : 



Order I. — Axonolipa. 



1. Dendrograptidi. — (Hydrothecaa dimorphous, larger nutritive and smaller 

 protective polyps, branching irregular.) 



(a) PHctyonema . — Nineteen species are recorded, and I), fiabelliforme and 



D. tuberosum are re- described. 



(b) Callograptus. — G. Salteri and G. elegans are described. 



(c) Dendrograptus. — Nine species are recognised and several figured. 



(d) Ptilograptus. — Four species are recognised, and P. acntus is described 



and figured. 

 (Freeh considers that Thamnograpsus, Inocaulis and Gorynoides are "incom- 

 pletely known, and their systematic position uncertain.") 



2. Dichograptidi. — (This includes the Dichograptidse, Leptograptida?, and the 

 Phyllograptidse.) Free-swimming hydrothecse, one kind only, branching dicho- 

 tomous. 



a. Sub-family Didymograptini (two main branches) : 



(a) Bryograptns. — B. Kjerulfi ( = P. Gallavei), B. retroflexus, B. ramosus, 



II. Hunnebergensis and B. sarmentosus. (He gives a table showing 

 the phylogenetic relationship of the genus.) 



(b) Goenograptus s. str.. G. gracilis and G. fragilis, and including 



Trichograptus. 

 Pterograptus, sub-gen. — P. elegans. 

 Pleurograptus, sub-gen. — P. linearis, Amphigraptus (A. divergent). 



(c) Bidymograptus. — In the group of I). Murchisoni he includes 



D. Murchisoni var. gemina, D. dentatus (indentus), D. v-fractus, 

 D. nitidus : in the group of D. fi,accidus {Leptograptus ex parte), 

 P). extensus, D. minutus, D. flaccidus ; and in the group (or sub- 

 genus) of JJ. gibbrrulus that species only. 



