138 
It will easily be seen that many, and partly important, questions 
are yet to be solved, — my own defects excluded — owing to 
the bad preservation of the material. The following observations some 
few ones, especially mentioned excepted refer to Eucarus segmentatus. 
1. Shape and Segmentation of the Body. 
The body of the Arachnids falls into three parts: the head, 
bearing the first four pair of appendages, the thorax, bearing two 
pairs, and the abdomen composed of a different number of segments. 
This theory which satisfactorily explains the singular position of 
the two last pairs of legs in most of the Acari is owed to the 
naturalist Dr. W. Sørensen and is shortly set forth by him and 
Dr. H. J. Hansen in their paper about ,,The Order Palpigradi 
Thor." (6 pag. 225); the main publication on this disputed theme 
ought to be expected with vivid interest. 
The head of Eucarus is' naturally divided into two distinet 
parts: the pseudocapitulum (pag. 145) and the proper head bearing 
the eyes. This last part is not sharply defined from the thorax 
which gradually merges into the 'abdomen. . Between the head and 
the thorax there is a short but distinct dorsal groove in front of 
the blue transverse spot on the first thoracic segment (Tab. IV 
fig. 1. 1). "The next groove between the two thoracic tergites is 
comparatively short and almost straight; the third one (fig. 1. .2) 
between abdomen ånd thorax, is bent forwards and goes from one 
margin to the other. It is most natural to draw the limit between 
the thorax ånd the abdomen at the last named groove, because it 
is much more marked than the preceding one. "The inner dorsal 
longitudinal muscular band begins at the first groove, and according 
to this fact, and because it bears the eyes, it is most natural to 
regard the part in front of it as the head. 
As there is no limitation betweeen the head and the thorax 
on the ventral side we may practically speak about a cephalothorax 
in Eucarus as im most other Arachnids. It ig narrow in front, 
here forming a semi-roof above the ;Pseudocapitulum, but it 
