69 



CONTRIBUTION TO A KNOWLEDGE OF AUSTRA- 

 LIAN HIRUDIXEA. Part vi. 



The Distribution 0¥'snv.HiRUDiNEA,\yiTYi. Special Rkference 

 TO Australian Forms, and Remarks on their Affinities, 



TOGETHER WITH REFLECTIONS ON ZOOGEOGRAPHY. 



By E. J. Goddard, B.A., B.Sc, Linnean Macleay Fellow of 

 THE Society in Zoology, 



Of the Australian forms enumerated in a list of species which 

 I have made, at least five genera are characteristic of Australasia 

 (in its ordinar}"^ geographical sense). Of these, three are aquatic 

 genera — Semilageneta, Diiieta, and Hirudobdella; the remaining 

 two genera, Geohdella and Phikevion, are land-forms. From this 

 it will be seen that we have characteristic generic representatives 

 of the IchthyohdellidcB (if Semilayeneta must be allotted a position 

 under the present classification), Herpohdellidoi and Gnathoh- 

 dellidcf. Some little interest attaches to Ozohranchus hranchiatus 

 from a distributional standpoint, in that the onl}' other known 

 species of the genus is that noted by Apathj^ in the Mediterra- 

 nean Sea. In connection with this, I have previously stated 

 that this genus is evidently always associated, under parasitical 

 conditions, with members of the Chelonia, in contradistinction to 

 the confinement of species of Branchellion to the Pisces. Chelone 

 mydas, the host of Ozohranchus hranchiatus, is distributed over 

 the Pacific, Indian, and Atlantic Oceans, so that, in all possi- 

 bility, this member of the Hirudinea has a very wide distriljution. 

 Oka, in 1895, described a species from Japan which he doubtfully 

 referi-ed to 0. Mendesi, and this, no doubt, is meant for 0. hran- 

 chiatus. Unfortunately I have not had the opportunity of 

 reading Oka's original paper, and have gleaned my information 

 from a reference made by Moore. 

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