11 



bear a different number of marginal teetb along Ibe upper and inner margin. 

 (PI. I, figs. Ic, 4 a and 5 a, pi. II, fig. 16). The immovable finger of the chela, which 

 is always placed upwards and inwards, bears below the marginal teeth an organ, 

 which is more or less plateshaped in Chelifer Geof. and genera related to it, while 

 it is shaped like a serrula in Chthonius C. K. and forms related to it (PI. I, figs. 1 c, 

 4a and 5a; pi. II, 3a-6a, pi. IV, fig. 4a); Ibis organ is according to its structure 

 named lamina or serrula interior. The immovable finger bears besides in at least 

 all the Panclenodaclyli a narrow plate, placed along outer side of the finger nearer 

 to the middle line of the body, which is designated the lamina exlerior. The 

 movable finger is either terminated in a more or less branched process, named 

 yalea (PI. I, fig. 4b, pi. II, 2a and 4c, pi. IV, 4c) or in a little marked rounded pro- 

 tuberance, through which the spinning glands, which are found in the céphalo- 

 thorax, debouch. The movable finger is besides below near to the inner margin 

 provided with a serrulisbaped blade, serrula exterior, which is either completely 

 fused with the finger (PI. II, figs. 2 a and 4 c) or more or less free distally (PI. I, 

 figs, la and 4b). The band of the antennae is, near the base of the movable finger, 

 provided with a number of peculiar hairs; the name flagellum has been given 

 to these hairs. 



I. Historical Remarks. 



In spite of the many interesting features, which a representation of the develop- 

 ment of our knowledge as far as the structures of the antennae are concerned should 

 provide, I have in this paper found it necessary to confine myself to the following 

 few remarks. 



A few authors gave alreadj' in tbe first half of the last century a rather good 

 description of these structures in different forms (viz. Tulk 1843, 30, p. 56; Scliiødte 

 1851, 31. p. 24, tab. I, fig. 2c, and in a less degree Menge 1855, 33. tab. I); but a 

 naturalist has nevertheless as lately as in 1889 (Daday 11. p. 166) represented these 

 very facts as being new; as a whole the rather slow progress in the studies of 

 these organs may partly be ascribed to a regrettable want of knowledge as far as 

 the results arrived at by predecessors and contemporaries are concerned, which is 

 a conspicuous feature in many papers on Chelonethi. It was chiefly in the years 

 from 1882 — 88 that several naturalists studied these organs parti j' in single forms 

 (Thorell 1882, 6. pp. 38— 39; Croneberg 1888, 45. pp.425— 427), partly from a more 

 systematic and comparative point of view (Hansen 1884, 9. pp. 523— 524; Canestrini 

 1885, 42); but all these broke entirely new ground, as the one did not know the 

 result, at which tbe other had arrived, and were of course unable to derive full 

 advantages of the progress, which was necessarily very much retarded. And it is 

 only recently owing to papers by Balzan (1890, 46. p. 406), but especially by Hansen 

 (1894, 49. pp. 227 — 229), that the real structures of the antennae have been under- 

 stood by most workers on the Chelonethi. though it was so by the most advanced 

 more than twenty years ago. 



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