236 EXTO.MDLÜtUSK TlDSKRIl T I 90 I . 



these glands extend through a large part of the cejjhalothorax, 

 and perhaps have their orifice in front of the third pair of limbs. 

 These excretory organs in reality arise in the second segment of 

 the abdomen, and after forming one or two convulutions run 

 into and straight through the thorax, to terminate between the 

 second and third pair of appendages. There being no Malpighian 

 tubules in the small animal, this simple pair of coxal glands would 

 seem to represent the only excretory organs, unless ...» But she 

 does not mention the following particulars. In the explanation 

 of the plates Gr.^ssi writes (p. 171): »glandola cefalotoracica 

 (dorsale) omologa alia glandola del Krohn dei Falangidi». In 

 the text and in footnotes on p. 234 — 235 Han.sen and Soren- 

 SEN have mentioned that the gland »which generally, though in- 

 correctly, is called the Krohnian gland» in Opilio?ics is a stink- 

 gland; it was discovered in 0/y. Lmiiatorcs and its secret men- 

 tioned by P. Gervais already in 1849; in 1S67 it was ascer- 

 tained by Krohx with regard to Op. Palpatorcs : later on W. 

 SoRENSEN and Loman have written on the gland. Furthermore 

 we have said: »Though we have only once in a way been for- 

 tunate enough to observe this gland (and even then scarcely in 

 its full length), we feel bound to say that Grassi's comparison of 

 this gland in Kocncnia is not correct. In structure the above- 

 mentioned tubular gland in Koi'Jirnia does not agree with the 

 pouch-shaped > Krohnian gland in Opiliones. On tlie other 

 hand, there can scarcely be any doubt that it corresponds to the 

 excretory glands which in the higher AracJinida [Aranete and 

 •» Arthrogastriy) just have their orifices on the sides of the cé- 

 phalothorax and not — like the Malpighian tubes of the Insects 

 — in the rectum». »And the structure of the afore-mentioned 

 glands in Kocnoda seems to be exactly the same as the excre- 

 tory ones in Opiliivicsy^ . It is clearly shown by these quotations 

 that Miss Rucker has only added some observations on the length 

 and the place of the orifice of these glands, which certainly have 

 been discovered by Grassi, but incorrectly interpreted l)y him, 

 while they have been mentioned and correctly interpreted by 

 Hansen and Sorensen. 



Miss R. mentions a ]iair of small diverticula from tlie tho- 

 racic and five ])airs of larger diverticula from the abdominal i)art 



44 



