HANSEN AND SÖRENSEN, THE TARTARIDES. 21 



segment, and in Scorpiones the spirades are placed nearer the 

 posterior than the anterior margin of the segment in question. 



8tiiik-()r1aiids. - Many years ago Wood Mason^ pointed 

 out that in Thelyphonus two very large glands open on the 

 terminal face of the last abdominal segment. The glands 

 stretch far forward in the abdomen ; according to the author 

 named their secretion reminds of acetic acid. Each glandular 

 opening is closed by a vaulted door equipped with strips; 

 these two doors which are large and easily seen with a 

 pocket-lens, are placed at each side of anus beneath the 

 flagellum. In a specimen of Schizornus cleaned with caustic 

 potash we found two long and wide glandular sacs stretching 

 from the twelfth abdominal segment forward about to the 

 middle of abdomen; the openings of these sacs are seen on 

 the terminal face of the segment named, equipped with doors 

 of similar structure (Pl. 2., fig. Il, o; Pl. 6., fig. 21, o) as in 

 Oxopoei. The existence of these very large and interesting 

 glands is an excellent character for the Uropygi, because they 

 are wanting in Amblypygi. Palpigradi and the other orders 

 of ours »Arachnida micrura». 



Org-aiis of Seiise. — The organs known to us in the Uro- 

 pygi can be referred to three categories, viz. eyes, sensory 

 hairs and »lyriform organs». As to the eyes we ref er to our 

 remarks on p. 6; the other organs must be mentioned here. 



The sensory hairs observed by us belong to two very dif- 

 ferent types. On Pl. 1., fig. 1 a it is seen that in Schizonius 

 one very long and very thin hair proceeds from the upper 

 side of tibia near its end on the three posterior pairs of legs, 

 while two similar hairs inserted near each other proceed 

 åt the distal end of the tibia of the first pair of legs. These 

 hairs originate from the bottom of small calicles — their in- 

 sertion is rather comphcate — and they are named »tactile 

 hairs». In Oxopoei the same hairs are found in the same 

 places^'. Their number and places of insertion af förd a good 



^ Wood-Mason, J. : Notes on the Anatoiny of the Scorpion Spider 

 {Thelyphonus). in Proc. As. Soo. Bengal, 1882, pp. ö9~60. 



- In 1803 Hansen (Organs and Characters in different Orders of Araoh- 

 nids; Entomol. Medd. Entom. For. Ivjöbenhavn, Bd TV., p. 137 — 256) 

 pointed out the tactile hairs in Thelyphonus , but he overlooked one of the 

 two hairs on the tibia of first pair of legs. 



