143 
oF Haswell’s specimens as no comment occurred as to this. His 
paper concerns specimens collected in places as scattered as Syd- 
ney, Masthead Island, Cooktown, Tasmania and New Zealand. 
But in another treatise (Haswell 1907 a), I have found a note to 
the effect that the Polyclad in question was collected at Sydney. 
This faet, combined with the actual differences between his de- 
scription and the features observed in my specimens, could raise 
some doubts about the justness of the identification. With regard 
to the considerable distance between the two localities of colleclion, 
it may already here be stated that this in itself does not forbid a 
presumption of identity. Yet, on the other hånd, the possibility of 
vicariating forms or species is not exeluded. Unfortunately the New 
Zealandian Polyclad fauna is too little known to allow conclusions 
from analogies to any great extent. Nevertheless we are aware 
that such a genus as Notoplana, with its great number of highly 
specialized species, is represented in both faunas with the same 
very characteristic species, N. ausiraliensis. What is known as 
regards other groups of marine animals is at least no hindrance 
for an identification. 
Turning now to a comparison between the specimens collected 
by Dr. Mortensen and Haswell’s description, we find in many respects 
very striking resemblances. On the other hånd, differences are 
also found. But these may be attributed either to actual variation 
in the species as to size, colouration, etc. or to the circumstance 
that certain features which are not easily detectable have been 
overlooked in the first description. For a doser comparison the 
value of figures cannot be overestimated, and I must deeply deplore 
the faet' that the important collection treated by Haswell has not 
been so profusely illustrated as it certainly deserved. Thus only a 
single figure, a schematic diagram of a sagittal section of the genital 
apparatus, is given for his new genus Enterogonia. 
Having no material of the Australian Enterogonia pigrans at 
my disposal, I cannot make the necessary revision or verification 
of Haswell’s description and complete it with some desirable details. 
Thus at present it is impossible to deejde with certainty the question 
as to the identity of the form from New Zealand with that from 
Australia. Under these circumstances I find it better to provisionally 
keep them apart than to make an identification which eventually 
