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



pair of legs.. The conical tubercles, which bear at their sum- 

 mits a compound eje furnished with a simple cornea like the 

 eye of Phalangium *, are to be regarded as chitinous processes 

 of the dermal skeleton, and at the same time as protectors of 

 the optic nerve, which is dilated in them in a cup-like form. 

 The remarkable position of the eyes of the Cyphophthalmida, 

 which occurs nowhere else among the Arachnida, led Dr. 

 Joseph t to the supposition that the CyphophtlialmidiB are not 

 true cave-animals, as in these the optic nerve is usually rudi- 

 mentary or frequently reduced to nothing. We can only con- 

 firm Dr. Joseph's supposition, as the species of Oihocellum 

 not only occurred under stones, but were also seen running 

 briskly about upon them J. The optic nerves also present no 

 reduction. 



The strongly developed chelicera (A) project from under 

 the anterior margin of the cephalic portion, and are directed 

 forward parallel to each other. The stem of the chela is 

 elongate ovate, and densely clothed with hairs on its surface. 

 The fingers slightly resemble in form the fingers of the palpal 

 chelae of the Scorpions and Chernetidffi ; there are also upon 

 each of them four or five long movable bristles, perhaps a 

 structure homologous with the olfactory rods of the Arthropoda 

 first discovered by Leydig §. Thus between the optic nerves 

 in Gihocellum a pair of nerves originate from the supra- 

 cesophageal ganglion, and run parallel to each other into the 

 chelicera [nervus antennarum) . In the stem of the chela the 

 nerve-trunk breaks up into fine terminal tufts, wliich are con- 

 nected by an extremely fine nerve-thread with the setfe, indi- 

 cated by us as olfactory organs ; in this way, I believe, the 

 deep morpliological significance, both of the seta3 and of the 

 chelicera, becomes manifest and distinct. These olfactory sette 

 appear to me possibly to correspond to the pectinately arranged 

 olfactory bacilli discovered by me in Chernetidfe ||, which also 

 issue from a tubercle on the stem of the chela. The homology 

 between the chelicera of the Arachnida and the antennge of 



* Ou the eye of Phalangktm, see F. Le_ydig, ' Das Auge der Glieder- 

 thiere, neueUntersuchungen ziir Kenntniss dieses Organs.' Tubingen, 1864. 



t " Ueber das Zusammentreffen von tbeilweisem und ganzlichem 

 Licbtniaugel mit Lageveriinderung, Verkleinerung &c. der Sehorgane," 

 Sitzungsb. der naturw. Sektion der Schles. Gesellsch. fiir vaterl. Cultur 

 (10 Nov. 1875). 



X Of the twelve specimens that I collected, ten were captured under 

 stones, and two running fi'eely about. 



§ " Ueber Geruchs- und Gehbrorgane der Krebse und Insekten," Archiv 

 fur Anat. und Phys. 1865, p. 265. 



II " Ueber neue indische Ohernetiden," he, cit. pp. 3 & 9, pi. 2. 

 figs. .3, 4, 7-9, 11. 



