Latreille. 



l*p to tlie present writing a little more than t\vo hundred .-uirl fifty 

 species of Arachnides have lieni descrihed as found in Tertiary deposits. ( M' 

 these alx.iit one hundred and ninety arc true spiders, while the remainder 

 are mostly Acarina I thirty-se\ m species), ( )piliones ; eleven species i. or ( '|ier- 

 m-tiil.-i' (nine species). All hut a single species, Aranea columbise, described 

 li.-!o\v. an- from European beds, and nine-tenths of them are preserved to us in 

 tlie F.ocene amlii-r W.-n- this means of restoring 1 the ancient Tertiarv fauna 

 unknown to n.-. our information at the present da\ p \\onld he hased upon 

 t\\ eiity-fonr species, although in addition to these half a dozen more a re 

 indicated hv simple ret'eivnee to genera or families. Thisnumberis already 



exceeded hv tliose described below from a single locality, Florissant alone 

 having yielded more than thirty species. Whether ue examine the Ameri- 

 can or Kuropean species preserxed in .stratified deposits \ Vr find an almost 

 total ahsence ofanv hut true spider-, or Araneides; iii each I including the 

 one herewith li-uivd > a -in^le species f A.carina ha^ been de,-crihed, though 

 a numlier of others are credited without description to Knropean strata. 

 In Prussian amher, on the coiitrarx , though Araneides are \astlv in the 

 majority, the other groups of Arachnides form "J7 per cent of the entire 



number of species, distributed mainlv in the three groups mentioned above. 



This greater proportion of true Araneide-, in Tertiary deposits, a pro- 

 portion exaggerated at the present day. can scarcel} ie well compared to 

 what we tind in the older deposits, from the extreme paucity of their 

 remains in the latter. Brodie has found oid\ a single species (which he 

 considers a true araneid) in the secondary strata of Kn-j'land. and the 

 KuropeaM Jura has furnished merely half a do/en arachnids ; nominal species, 

 perhaps reducihle to four), of which only a single one is referahle to the 

 Araneides, I la -.-hides, considered one of the A ^deludes hv \\'e\ eiitn r^h. 

 In the paleo/.oic formations, again, ;i dozen species are known, all hut three 

 of which have heen considered scorpions, I'hrynida- or ( 'hernetid;e, or else 

 placed in their vicinity, while one of the other three lias not heen placed 



45 



