238 M. A. Stecker on a new Genus of Arachnida. 



On the lateral margins of the second and third ventral half- 

 rings the orifices of the tracliece are visible. We distinguish 

 therefore, as in the Pseudoscorpiones, two pairs of stigmata *, 

 one pair belonging to the second, and the other to the third 

 segment. Their function is divided between them as follows. 

 The first pair gives origin to two great tracheal stems uniting 

 below the hjpopodia of the last pair of legs into one great 

 trunk, which goes into the cephalothorax and is there much 

 ramified. The second pair of stigmata, which occur in the 

 third abdominal segment, bear a structure analogous to the 

 tracheal lungs f, which occurs also in other Arachnida (/S'e'^es^rza, 

 DysderUj Argyroneta) in the form of tracheal tufts, and is 

 also represented in the Chernetidffi [ChtlioniuSj Obisium). 

 The individual tracheae pass without ramification through the 

 whole abdomen. The flat trachea originating from a ti'ans- 

 verse cleft of the spinnerets, discovered by C. Siebold J, do 

 not exist in Gihocellum. The stigmata also are differently 

 formed. The second pair of stigmata resemble in structure 

 the stigmata of the larv^ of Lamellicorn beetles ; for here also 

 there is a chitinous plate perforated like a sieve. The only 

 difference is that in the Lamellicorn larvge the plate is per- 

 forated only at the periphery, but here over the whole surface. 



The sjmining-glands are present. Dr. Joseph, indeed, was 

 unable to observe them in CyjjhojjJithahnus [I. c. p. 246) ; but I 

 am of opinion that they occur in that genus also, and were 

 overlooked in consequence of their peculiar position. The 

 spinnerets, as in the Chernetidae, are not placed at the ex- 

 tremity of the abdomen, but on the posterior margin of either 

 the first [Gthocellum) or second (Chernetidjfi) abdominal seg- 

 ment. In Gihocellum we distinguish two pairs of small 

 spinnerets, which are furnished with three difterent glands 

 {glandulm aciniformeSy ttihuliformes, and ampidlacem) , in com- 

 binations of two and three. In their structure they resemble 

 the Araclmidan spinning-glands discovered and described by 

 Lyonet§, Wasmann ||, Blackwall% Meckel**, (Effinger ft, 

 and others. 



* In Cyphophthulmits there is only one pair, opening in tlie acute lateral 

 angles of tlie tirst ventral half-segment. 



t R. Leuckart, "Ueber den Bau und die Bedeutung der sog. Liiugen 

 bei den Arachniden,'' Zeitscbrift fiir wiss. Zool. i. 1849, pp. 246 et seqq. 



X Siebold, loc. at. p. 535. 



§ Mem. du Mus. d'Hist. Nat. 1829, tome xviii. p. 387, pi. 19. figs. 6-12. 



[1 Archiv des naturw. Ver. in Hamburg, 1840, p. 20, tigs. 31-40. 



II Trans. Linn. Soc. vol. xviii. p. 220 ("1841). 



** Miiller's Archiv fiir Anat. und Phys. 184G, pp. 1-74, Taf. 1-3; the 

 Spinning-apparatus, "Arachuidium," pp. 50-56, ligs. 38-49. 



tt Archiv fiir niikr, Anat. Band ii. pp. 1-12, Taf. 1 (1866), 



