M. A. Stecker o« a new Genus of Aracluiida. 231 



conical tubercles, and the strongly developed chelicera, do 

 not leave us long in uncertainty as to where our animal 

 has to be ranged in the system of the Arachnida. This 

 close relationship, however, becomes still plainer when we 

 subject the animal to a thorough microscopical examination; 

 but then also the histological and anatomical differences, 

 which will be indicated in the following description, come 

 forth clearly and distinctly. 



The slxin of the two genera presents notable differences. 

 In Cyphopldhalmus the chitinous mass is in many places so 

 accumulated that the cuticular layer acquires a thickness and 

 resistency unusual among Arachnida, and, as Dr. Joseph re- 

 marks (Nachtr. p. 270), gradually assumes a similarity to the 

 carapace of the Chelonia. Frequently also the otherwise soft 

 and extensible cuticular deposits of the interspaces of the 

 individual abdominal segments become so strongly chitinized 

 that the whole animal is regularly enclosed in a soj-t of 

 chitinous shield, by which, however, as a matter of course,' 

 not only is a limit set to the increase of the volume of the body, 

 but the observation of the more delicate organs existing in the 

 abdomen is rendered difficult. Under high powers the cuticle, 

 like that of the Chernetidas *, appears to be furnished with 

 rows of circular chitinous granules, regularly dispersed in 

 the lamellae ; the number of these becomes much smaller in 

 the interspace of the abdominal segments. 



From this formation of the cuticle the skin of Gihocellum 

 differs essentially. Even with the aid of high powers I have 

 not yet succeeded in observing the chitinous granules in the 

 brownish cuticular lamellae. Only on the cephalothorax and 

 in the cuticle of the superior abdominal rings are there a few 

 irregular accumulations of chitine, such as we have had the 

 opportunity of observing also in several genera of Cher- 

 netid^t [Ghthonius^ Megathis, Ohisiuni). The chitinization, 

 therefore, is here also to be regarded as only partial, and 

 greatly reminds us of the cuticular formation of Phalangium 

 opilio\] and by this means also the already mentioned un- 

 usual extensibility of the cuticle is attained. 



The pore-canals, so characteristic of the dermal skeleton of 

 the Artliropoda §, occur very sparingly ; the cause of this is 



* See the fig-ure of the cuticle in the Chernetidae in my memoir, " Ueber 

 neiie indische Chernetiden," in Sitzungsb. Akad. Wiss. Wien, 1875, 

 p. '5, pi. 2. figs. 5 & G. 



t Steeker, he. cit. pi. 2. 



X F. Lej^dig, "Ziim feinercn Ban der Arthropoden," Miiller's Arch, fiir 

 Anat. und Phys. 1855, pp. 381-384. 



§ Valentin, Repertorium I'iir Anat. und Phys. Bd. i. 1830; 



