M. A. Stecker on a new Genus of Arachnida. 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 ditferences, 

 which will be indicated in the following description, come 

 forth clearly and disthictly. 



The sJi-in of the two genera presents notable differences. 

 In CypJioplithahnus the chitinoiis mass is in many places so 

 accumulated that the cuticular layer acquires a thickness and 

 resistency unusual among Ai*achnida, 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 sort 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 Ghernetidae *, appears to be furnished with 

 rows of circular chitinous granules, regularly dispersed in 

 the lamellte; the number of these becomes much smaller in 

 the interspace of the abdominal segments. 



From this formation of the cuticle the skin of GiboceUum 

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

 not yet succeeded in observing the chitinous granules in the 

 brownish cuticular lamellge. Only on the cephalothorax and 

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

 irregular accumulations of chitinc, such as we have had the 

 opportunity of observing also in several genera of Cher- 

 netidtef [Chtlioniusj Megathis, Ohisium). The chitiiiization, 

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

 greatly reminds us of the cuticular formation of Phalanc/ium 

 opilioX] 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 Arthropoda §, occur very sparingly ; the cause of this is 



• See tlie figure of the cuticle in the Chernetidoe in iny memoir, " Ueber 

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

 p. 5, pi. 2. figs. 5 & 6. 



t Stacker, loc. cit. pi. 2. 



X F. Leydig, "Zum feincnMi Bau der Arthropoden," Miiller's Arch, fijr 

 Auat. und Pliy-*. ISo^, pp. 881-;}S4. 



§ Valentin, Repertoriuni i'iir Anat. und Phys. Bd. i. 1830. 



