702 Scolopendrella and its Position in Nature. |September, 
Podure, and which we have designated as the collophore; the 
occurrence of this opening on the fourth ring indicates that in 
Scolopendrella we may distinguish between a series. of three 
thoracic segments and about nine or ten abdominal segments, 
Now examining the supposed myriopodous features of Scolo- 
pendrella, we find that they consist in the identity in form of all 
the body segments behind the head, and in the fact that each seg- 
ment bears a pair of functional several-jointed legs. In Machilis, 
however, the thoracic segments grade almost imperceptibly into 
the abdominal arthromeres or somites; though in Lepisma, and 
especially in Japyx and Campodea the thoracic segments are 
clearly differentiated from the abdomen. 
Now the possession of functional jointed abdominal legs by 
Scolopendrella does not imply that it is necessarily a Myriopod ; 
we have seen that the feet differ in important respects from those 
of the centipede, and the presence or absence of abdominal feet is 
not an ordinal or very important character, for the head characters 
are both in Hexapods as well as in Arachnida and Myriopods, of 
the most importance in separating orders and subclasses. Turn- 
ing now to the Thysanura, we see that Campodea has a series of 
one-jointed abdominal appendages which are, as we have observed, 
very movable while the insect is running. They appear to be 
rudimentary locomotive appendages. Those of Machilis are much 
better developed and are still more leg-like ; the two pairs of ter- 
minal shorter stylets of Lepisma we have observed are used as 
prop-legs, so that the transition from the legs of Machilis to Sco- 
lopendrella is not a very abrupt one. We therefore conclude that 
the sum of the characters of Scolopendrella are Thysanurous, and 
that the homogeneity of the body segments and the five-jointed 
legs which has led to their being regarded as Myriopods, have 
misled naturalists; Scolopendrella seems to us to be only anal- 
ogous to the Myriopods as regards its feet. The presence of the 
two caudal stylets is also a Thysanurous feature; these organs We 
should regard as homologous with the stylets of Lepisma and the 
forceps of Japyx. Menge and Ryder regard them as spinning 
organs, and we would agree with this opinion, as in one of the 
specimens from Bohemia, we could see the ducts leading into each 
stylet, from one of which a silken thread projected. From 
Menge’s statement that the opening of the oviduct lies imme- 
diately above the anus, we should dissent on general grounds, as 
