234 
from these papillæ the animal appears to be a female normally 
developed. 
As I have not seen any case of that sort in freeliving Nema- 
todes mentioned in literature I have figured the organs dealt with. 
Trilobus pellucidus Bastian. 
1865. Bastian, p. 100. PI. IX. figs. 23, 24. 
1884. De Man, p. 76. T. XI. tig. 44. 
This species is not rare in Denmark, but its distribution 
is probably different from that of the above named species as 
they have not been found together. I found the T. pellucidus in 
a bog by Lynæs from which locality several specimens were 
collected. Moreover it has been taken at the Kandesteder in Jut- 
land, in sandy mould, and finally one specimen has been taken in 
Ordrup Mose in water. 
According to my experience it must be supposed that of the 
two species of the genus Trilobus, Tr. gracilis is particularly a 
freshwater - form while Tr. pellucidus is attached to brackish 
water. I may note therefore, that Bastian indicates gracilis 
to be found „about the roots of Ruppia maritima from brackish 
water“ while pellucidus is found in „mud from bottom of ponds“. 
De Man notes that gracilis „bewohnt nicht nur die feuchte 
Erde, welclie von stissem oder brackischem Wasser durchtrånkt ist. 
sondern auch das siisse Wasser selbst, in Gråben und Teichen“. 
Prismatolaiinus dolichurus de Man. 
PI. III. fig. 18. 
1384. De Man, p. 80. T. XII. fig. 47. 
I have seen this species only once among material from Ly¬ 
næs and only one specimen. It was found together with Mononchus 
papillatus and Plectus granulosus on roots of plants originating 
from the little bog behind the churcli. In this species there is a 
peculiarity at the oesophagus which de Man does not mention in 
his text but which is visible in his figure; this peculiarity con- 
sists in a rather conspicuous constriction by which the proximal 
