PART VL-FOSSIL SPIDERS. 

 OHAPTEE XY. 



ANCESTRAL SPIDERS AND THEIR HABITS. 



The interest which attaches to the spider fauna of the present era 

 naturally reaches backward to those of geologic time. I therefore under- 

 take a sketch of the fossil remains of spiders, with particular view to 

 gaining, if possible, some key to ancestral habits. The material for our 

 review is not abundant, but fortunately we have sufficient data to give 

 our inquiry an intelligent interest. 



I. 



According to Scudder,' one hundred and ninety species of spiders have 



been discovered from the Tertiary deposits of Europe. Mr. Scudder de- 



scribes thirty-two from America in his work on the Tertiary 



Sniders Insects, of which fourteen are Orb weavers, being forty-four per 



cent of the whole number of species. The proportion of known 



fossil Orbweavers in America is much greater than in Europe. 



A notable addition to our knowledge of the spiders of Tertiar}' Europe 

 has been made by Gourret in a paper on those of Aix, in which, among 

 others, eighteen species are described, including two of Erisoidse, two of 

 Lycosoidse, one of Theraphosoidse, one of Dysderides, two species of Her- 

 sillioida;, two species of Erocteroidae, one Enyoidse, none of which families 

 had been before found in European rocks, and the last two named not 

 even in amber. ^ 



Of the fossil spiders of Europe, one hundred and sixty-eight are de- 

 scribed from enclosures within amber, forty-one only from the rocks. It 

 will thus be seen that wliile Europe is much riclier in spiders w'hen the 

 amber fossils are included, America has yielded more than thi'ee-fourths as 

 many from the Tertiary rocks and one from the Carboniferous. 



The fossil spiders found in America are distributed as follows : Salti- 

 grades, three species of Attids; Laterigradcs, three species of Thomisids. 

 Tubitclariae : Dysderides, one species ; Drassides, five species ; Agalenades, 

 two species. Retitelarite : Theridides, four species. Orbitelarise : Epeirids, 

 fourteen species.'' Arthrolycosa antiqua is probably a Territelarian. 



' Tertiary Ineecte of North America, pages 48-90, U. S. Geol. Survey of the Territories, 

 Vol. XIII. ^ Ibid., page 52. ' Ibid., page 49. 



(446) 



