70 AUSTRALIAN HIRUDINEA, VI., 



Branchellion, which is represented by at least three definite 

 species in Australian waters, is a universally distributed genus, 

 being noted from the Atlantic, Pacific, and Indian Oceans. 

 Pontohdella is likewise a cosmopolitan form, and is represented 

 by at least one definite characteristic Australian species, Pontoh- 

 della australiensis. P. macrothela was originally found by 

 Schmarda in Jamaica, and Blanchard has noted the same species 

 from Sumatra; so that the presence of this species in Australian 

 waters would seem to indicate that it is universally distributed. 

 Semilageneta, represented, up to the present time, by a single 

 species known from no other part of the world, is interesting in 

 that it is ap])arently intermediate between the Ichthyobdellid 

 and Glossiphonid forms, as noted previously. No characteristic 

 representative genus of the Glossiphoniidce is to be noted in Aus- 

 tralasia. Three genera, Glossiphonia, Placobdella, and Microh- 

 della have been found, the former in Australia and Tasmania, 

 the latter two in New Zealand. The occurrence of Microbdella 

 in the latter place is interesting, in that it was discovered almost 

 exactly at the same time as Moore discovered and described the 

 type-species, M. hianmdata, from Carolina, U.S.A. As I have 

 previously pointed out, no terrestrial member of the Rhynchob- 

 dellidcB has ever been noted in any part of the world, and, in 

 view of this, the occurrence of these freshwater forms in Austra- 

 lasia, in contradistinction to the limited distribution of the 

 terrestrial members of the Hirudinea, serves as excellent corro- 

 borative evidence of the cosmopolitan distribution of freshwater 

 forms of life, which is due, no doubt, to a great extent to the 

 means of transmigration offered by birds, etc. 



Among the Herpohdellidce, we find in Australia the cosmo- 

 politan genus Herpobdella, and a genus, Dlneta, confined, so far 

 as is known, to Australia. The latter form, however, as has been 

 noted previously, is very closely allied to the former, and, again, 

 both these genera are freshwater forms. 



The Gnathobdellid representatives fall into two groups, viz., 

 aquatic and terrestrial. Among the former are comprised repre- 

 .sentatives of three genera — Li7nnobdella, Hirudohdella, and 



