22 
The Queensland Naturalist. 
July, 1925 
Tho anatomical characters of the forms are as 
follows : — 
Phreodrilus — Spermathecae and i)ores distinct. 
Wall distinctly g-laiidular. 
Astacopsidrihis — Spermatlieeae distinct. l)nt ducts 
comninnicatin^- with female ducts. Wall dis 
tinetly g^landular. 
Gondwanaedriius— Spermathecae distinct, but duets 
commiinieatinjr with male })enial chamber. 
Tasmauiaedrilus — Spermathecae evanescent and 
ducts absent. Wall thin and non-glandular. 
Phreodriloides — Spermathecae and ducts absent. 
It will be seen that we have now an undoubtedly 
complete anatomical sericvS. and that the family whicii 
at first known only by the genus Phreodrilus. was con- 
sidered so unique in regard chiefl^’ to its setae and si)er- 
mathecae, can be s])Iit into genera whose marked 
differential characters concern both these structures. 
Anatomical evidence sup])orts the idea that the 
family is an ancient assemblage, and their habitat taken 
into consideration in conjunction with their circumpolar 
distribution, is interesting. With tlie exception of one 
genus, which is unique amojig tin' grouit in that it lives 
in close semiparasitic association with the freshwater 
crayfisli — Astaeo])sis — of Australia, tliey are restricted 
to cold habitats. These conditions are obtained in some 
cases through tlie latitude of the habitat, in others by 
extreme bathymeti’ical isolation, assisti'd by the s(‘asons. 
In South Africa, for example, they have l)e(‘n eollect(*d 
on Wellinglo]! Mountains. Stellejihosch Mountain, and 
Table Mountain, but further, not only does investigation 
shoAv that they are inhabitants of mountains solely, bur 
also that they disappear in some manner or otlnu* — no 
doubt into the soil — during tlu‘ hot months of the year. 
In noting tlnur I’cstriction to cold habitats and to 
tlie Southern Ilemispluu'c, it must he Imrin* iji mind that 
no re-])resentatives lia ve been found in the Northern Ilemi- 
.S])hf‘re, which has been mneh more seriously investigated 
in the past. This is very significant. The fact that they 
are restricted to habitats with low temperatures may be 
rationally inter])reted as signifying that sncli a commoii 
feature is characteristic of the group, and in all pro- 
