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proximal of which are entirely devoid of spots, while, 
however, a little spot was found on the 6th joint; further 
out on the telson they become larger by degrees, and the 
largest ones are found on the 16th—18th joint, whereupon 
they are redecreasing little by little in size, but still found 
on the very last joint. Only one spot is found on each 
joint, lying close to the basis (Tab. III, fig. 4, m). 
I have found nothing in the literature about the 
structure and significance of the telson-spots; Stoliczka, 
however, has declared the spots on the 12th abdominal 
segment to be glands, whereupon Thorell makes the 
striking remark: »nescio qua ratione« (op. cit. p. 364). 
It is a positive fact that the mentioned spots are 
organs and not common colour-spots. It remains a question, 
however, if the organs of the 12th abdominal segment 
and of the telson are of the same or of a different nature; 
my investigations issued in the result that as to struc- 
ture no essential difference is existing, and i am thus 
going to treat it in one. In Thelyphonus the chitine 
is very thick and its 2 layers (see Gauhert op. cit. p. 
34—42) very readily observed; cuticula is often even 
sealing off very easily. The cuticula (Tab. II, fig. 5, c) 
is several times thinner than hypodermis (fig. 5, h); on 
the mentioned light spots the cuticula is exceedingly 
transparent, clear, faint light yellow and 
without pores, while hypodermis is totally 
wanting. On segments cleaned in caustic potash the 
edges of hypodermis are seen to be projecting inside 
above the thuswise shaped cavity in such a way that 
the aperture on the interior side (fig. 4 and fig. 5) is 
smaller than the light spot of the cuticula. The entire 
cave is replenished with a peculiar mass (fig. 5, m) 
similar to connective tissue, not showing neither gang- 
lionic nor glandular structure; an excretory duct through 
the cuticula does not at all exist. Of what nature are 
