68 Earlier Criticisms of Stecker's Treatises 



membraiie removed from the animal produced a " secretion " of a cellular stratum which 

 in 24 hours attained a thickness of one-tenth, and in 48 hours a thickness of two-thirds of 

 the matrix. — The reason why no writer appears to have had any hesitation, from a histological 

 point of view, in accepting the histological statements of Stacker, is probably this : that he 

 professes to have made use of the ordinary reagents for microscopical research. At the same 

 time it may have been a concurrent cause, that Stacker was known as the author of several 

 purely histological papers published during 1876 and 1877 (viz. Ueber die Entwickelung dar 

 Chthonius-Eier im Mutterlaibe und die Bildung des Blastoderms, — Uebar die Furchung und 

 Keimblatterbildung bei Galyptraete, — Die Anlage der Keimblatter bei den Diplopoden (Chilo- 

 gnathen), Ein Beitrag zur Entwickelungsgeschichte der Myriopoden). 



At the hands of a couple of systematic writers the papers of Stecker on Gibocellum 

 sudeticum received much less appreciation. According to his own statements (a, pp. 241, 242; 

 b, pp. 293 — 296) his new genus was most nearly related to the Cyphophthalraoids described 

 by other writers, Gyphophthalmus, Fettalus and Stylocellus. Stecker states that he " found 

 himself under the necessity" of erecting the whole of this group into an independent order 

 Cyphophthalmidse, of which he says (a, pp. 240, 241), " I have already several times had 

 occasion in this memoir to show clearly the near relationship of the Cyphophthalmidae on 

 the one hand with the Phalangiidaj [i.e. the Opiliones], and on the other with Chernetidse " ; 

 nevertheless he j^laced Phalangiidse [i.e. Opiliones] and Oyphophthalmidis together so as to 

 form a higher unity : " Opilionea." At the same time he divided his new order Cyphoph- 

 thalmidse into two families : Cyphophthalmin^ comprising the three genera already known, 

 viz. CyphupJdhalmus, Fettalus and Stylocellus\ and Gibocellinte, which only consisted of Gibocellum. 

 The difference between the two families was according to his statement, that (Jibocellinse had 

 two pairs of eyes, both placed upon obliquely ascending conical tubercles, two pairs of spiracles, 

 and mamillse at the base of the abdomen. 



That Gibocellum must be a very remarkable animal, by its anatomical structure, could 

 not but strike all Arachnologists, but none of them would accept Stecker's new order : all 

 of them excepting Thorell referred Gibocellum without hesitation to Opiliones. When the 

 last-named author had studied his first species of Stylocellus (and Siro) he recognized that 

 there must be a considerable difference between real Sironoidte (Cyphophthalmoidffi) and 

 Gibocellum as described by Stecker. He expresses himself thus : (c, p. 33) " non magis recte 

 fecisse mihi quidem videtur Stecker, quum Gibbocellum ad eundem ordinem ac Cyphophthalmum 

 sive Sironem retulerit," and with regard to Stecker's having placed Gibocellum near both 

 Opiliones and Chelonethi Thorell, who was not by any means blind to the defects of Stecker's 

 papers, considered that Gibocellum ought to be referred to Chelonethi, and adduced in 

 support of this view several points of Stecker's description. 



Sorensen, in his treatise on the anatomy of Laniatores, had been unwilling to take 

 notice of Stecker's papers on this extraordinary creature ; but the fact that Thorell had 

 referred Gibocellum to Chelonethi compelled him to do so, and he devoted several pages of 

 his next systematic paper (d, pp. 560 — 567) to a criticism of Stecker's treatises, showing that 

 this writer possessed but little knowledge of either Opiliones or Clielonethi, and that his 

 study of Gibocellum must have been very imperfect. With reference to those characters on 

 account of which Thorell had thought that Gibocellum, ought to be reckoned among Chelonethi, 



' Stecker (6, p. 296) leaves it undecided to which of these should tlierefore be noticed that Westwood had overlooked 

 two families Stylocellus Westw. ought to he referred. It the real ("sessile") eyes in S. sunuitranus. 



