324 Dr. L. Béhmig on the Excretory Organs kc. 
G. damarensis, a white-spotted form, certainly occurs in 
Angola, for the British Museum contains a specimen collected 
there by Dr. Welwitsch, and some of the forms may be referred 
to this species; but most of the specimens are rather young 
for determination. G. hottentottus, G. damarensis, and 
G. Bocaget, having the naso-frontal suture of somewhat the 
same pattern, the skulls are difficult to distinguish when 
young. ‘The occipital spot is undoubtedly a variable cha- 
racter, as I find in normally unspotted forms, such as G. Nim- 
rodt, an occasional specimen with a small white spot, and in 
the normally large-spotted form, G. Darling?, an occasional 
specimen turns up with only a very small white spot; thus it 
may be possible outwardly to almost perfectly match speci- 
mens of these two otherwise very widely distinct species ; 
this only shows how necessary it is to have far larger series 
of these animals before we can say whether age, sex, or 
season has anything to do with their varying exteriors. 
XXXVI.—On the Excretory Organs and Blood-vascular 
System of Tetrastemma graecense, bohmig. (A Provi- 
sional Communication.) By Dr. L. Boumic, of Graz *. 
THE freshwater Nemertine which I observed in the year 
1892 in a reservoir in the Botanical Gardens here I have 
again discovered in greater numbers in the same place, and 
have been enabled to submit it to closer investigation. I 
devoted my attention especially to the excretory and sexual 
organs, and now give a short statement of some of the results 
of my researches. 
Although the plates for my memoir on Tetrastemma 
graecense were finished a considerable time ago, the publica- 
tion of the paper itself has been greatly delayed, partly in 
consequence of my professional duties and partly owing to 
the examination of a land Nemertine found in the hothouse 
of the local Botanical Gardens. 
In specimens to which a moderately strong pressure has 
been applied there is readily recognizable on each side of the 
body a system of clear ramifying canals, from 4°26 to 11°36 wu 
in diameter, which communicate one with another and per- 
meate the animal throughout its entire length. In the anterior 
extremity of the body, in the region of the brain and in 
front of it, 1 observed only a single canal of larger size, which 
was disposed in manifold sinuosities and loops, and ultimately 
became broken up into a fine close-meshed network of very 
small canalicules ; at the posterior end of the body I failed 
to discover a terminal plexus of this kind. Into the coarser 
* Translated by E. E. Austen from the ‘Zoologischer Auzeiger,’ 
Bd. xx. No. 623 (February 1, 1897), pp. 33-36. 
