410 MR. H. M. BERNARD ON THE CHERNETID^. 



Notes on tlie Chernetidce, with special Eeference to the Vestigial 

 Stigmata and to a new form of Trachea. By Henry M. 

 Bernard, M.A. (Cantab.). (From the Huxley Eesearch 

 Laboratory, Eoyal College of Science, London.) (Com- 

 municated by "W. Percy Sladen, Sec. Linn. Soc.) 



[Read 20th April, 1893.] 



(Plates XXXI. & XXXII.) 



In a short paper* containing additional evidence as to the origin 

 of tracheae from setiparous sacs, I stated that I had discovered 

 an Ohisium vrhich, in addition to the ordinary tw^o pairs of 

 stigmata on the second and third abdominal segments, had also 

 seven pairs of rudimentary, or rather vestigial, stigmata on the 

 seven remaining abdominal segments. 



The specimen on which these vestigial markings were first 

 found was brought from the Thliringer Wald, and was macerated 

 in boiling caustic potash (figs. 1 & 1 «, v.s.). I am now in- 

 debted to Dr. Griinther, F.E.S., for kindly placing at my disposal 

 six alcohol specimens from bottles labelled " Ohisium museorum^' 

 and " O. sylvaticmn or carcinoides.^^ Of these, four were cut 

 into serial sections ; one, owing to some extraordinary hardness 

 in the abdomen, resisted all elforts to cut it, the razor bending 

 and sliding over it ; the remaining specimen was boiled in caustic 

 potash. 



No trace of these vestigial stigmata could be found in the 

 sections, but in the macerated specimen (labelled O. sylvaticum, 

 figs. 2 & 2a) they were imftnediately found, though differing 

 in position from those on the Thliringer specimen. The object 

 of this paper is to describe the results of my investigation of 

 these interesting markings. At the same time, a brief description 

 of certain new points which have come to light in the course of 

 this investigation can hardly fail to be of interest. Since Menge 

 (6), there has been only one paper (by Croneberg (2)) dealing 

 specially with the anatomy of the Chernetidse, although observa- 

 tions on single points have been recorded. 



The outer form of the Chernetidse requires no description. 

 The chief point of importance morphologically is the relation of 

 the basal regions of the chelicerse to those of the pedipalps. The 

 Chernetidse agree with Oaleodes, the Araneidse, and, so far 



* Ann. & Mag. Nat. Hist., Jan. 1893. 



