212 Proceedings of the Royal Society of Victoria. 



movement. It has not yet been ascertained that the New South 

 Wales is identical with the Victorian, which is, however, certainly 

 the same species as the one named by Professor Blanchard from 

 Tasmania. 



So far as is known at present the land leech is not found in 

 South Australia, a fact to be accounted for, doubtless, by the 

 dryness of the atmosphere, and lack of moisture in the gullies. 



This little animal varies mucli in size. When contracted in 

 spirit some specimens are but 7 or 8 mm. in length, others — the 

 Tasmanian — measure from 25 to 30 mm. 



Whitman^ in his paper on the leeches of Japan says : " The 

 Australian species, for which I am indebted to Mr Haswell, 

 differs from all other species, that I have thus far examined, in 

 having only two jaws. The latero-ventral jaws are present, but 

 the median dorsal jaw is entirely absent. This remarkable 

 distinction, taken together with the fact that the genital orifices 

 are separated by seven and a half rings instead of five as in 

 the case of most other land leeches, seems to make necessary the 

 establishment of a new genus, for which I propose the name 

 Geobdella." 



This evidently diflfers from the leech under investigation, for 

 though the lattter possesses but two jaws, there is no doubt 

 whatever that the genital openings are separated by four rings 

 only, which is an indication that a typical segment consists of 

 four annuli. Until Professor Blanchard's recent work it was 

 generally stated that in the Gnathobdellidte each unabbreviated 

 somite possessed five annuli. Many species belonging to this 

 family, however, have been shown to form exceptions. Professor 

 A. Oka in his paper on "Some new Japanese Land Leeches" (1895) 

 lias described three new species belonging to an entirely new 

 genus, to which he gives the name Orobdella. The number of 

 rings in an unabbreviated somite, characteristic of this genUs, 

 -varies, but is' constant for each species. Thus O. ivhii}nani\\'a.% 

 ill all eighty -eight rings, each complete somite consisting of four 

 rings. O. ijimni one hundred and twenty-nine with six forming 

 a segment, and O. octonaria one hundred aiid seventy-one, with 

 somites of eight rings each. 



1 Q.J.M.S., No. 26, 1886, p. 317. 



