On EUROPEAN SPIDERS. 83 
dilated at the base. On the difference in the form of the maxillæ BLACK- 
WALL appears however to have laid no especial weight, for his Neriene 
longipalpis for ex. has unquestionably the maxille strongly dilated at the 
base, and the maxillæ of Neriene trilineata do not, as far as I can see, differ 
in form from for ex. those of Linyphia montana (CLERCK). The distinction 
then must be founded on the difference in the relative length of the legs; 
and the consequence is, that species so heterogeneous as for ex. JVeriene 
( Erigone) longipalpis and N. trilineata (Lin. bucculenta) have been united in 
one genus with N. marginata (Lin. clathrata SUND.), which accordingly is 
made not to belong to the same genus as for ex. Linyphia pratensis 
BLACKW.! That too much weight ought not in these genera to be laid on the 
characteristics derived from the relative length of the legs and a somewhat 
different form of the maxillæ, has nevertheless not escaped the observation 
of BLACKWALL, for he himself says in his account of his Neriene dubia (p. 
289) that even "the sexes of the same spider frequently differ in the rela- 
tive length of the legs and in the form of the maxille”. — The genus 
Neriene ought, in my opinion, to be wholly suppressed and its species dis- 
tributed among Linyphia, Walckenaera and Erigone, in such wise that the 
species that have scattered spines on their legs be assigned to Linyphia, and 
of the others those, of which the maxillæ are greatly dilated at the base, 
to Erigone, and the rest to Walckenaera. 
The numerous genera which MENGE has separated from Linyphia, 
I cannot adopt, as they appear to me almost exclusively based upon minute 
modifications of the organs of copulation ?), frequently only discoverable by 
means of the microscope. Compare what we have said on this subject in 
our remarks on the genus Æpeira, p. 54. 
1) This of course does not prevent our acknowledgement of the great importance 
of MENGE's researches on the subject of the more detailed structure of the sexual or- 
gans, which previous to him had been almost entirely unknown, and whereby a new 
and highly interesting field for investigation has been opened. It is probable that 
the results obtained by this species of research will have a certain influence on the 
classification of spiders, as soon as they have obtained a wider compass, and a 
richer store of materials of observation has been aecumulated. But as yet it is per- 
haps too early to attempt to deduce from the modifications of these organs the de- 
cisive characteristics of genera, for we have as yet too little knowledge of what 
eonnexion these modifieations have with the different form or arrangement of other 
organs of acknowledged systematie weight, e. g. the parts of the mouth, the extre- 
mities and the eyes. It appears to us, that similarities or dissimilarities in the struc- 
ture of the organs of copulation is far from always indicating a corresponding simi- 
litude or dissimilitude in the organisms generally; at least species which are very 
