SCUDDER. ] TERTIARY LAKE BASIN OF FLORISSANT. 287 
some extent, in the American fauna, and (excepting, as before, the Dys- 
derides) in the European rocks. Exception should perhaps be made 
for the six species of the remarkable amber genus, Archaea, the posi- 
tion of which in the Laterigradaeis uncertain, and so marked in the ta- 
ble above. The relation brought out by this table is certainly striking, 
but it should, at the same time, be noticed that the Drassides and The- 
ridides, and especially the latter, are enormously represented in the 
Baltic amber, and, in comparison with them (though not by any means 
to the same extent in comparison with the other groups), feebly repre- 
sented in the stratified deposits of Europe and America. 
A comparison of the percentage of representation of the larger groups 
in the different horizons of tertiary times in Europe with that of Floris- 
sant seems to indicate a greater difference between the latter deposits 
and those of the upper miocene of Oeningen than between the same 
and either the lower miocene of Rott or the upper eocene of Aix and the 
Baltic amber; and although the proportionate numbers of Tubitelariae 
and Orbitelariae of Florissant, and especially the former, are more nearly 
like those of Rott, the representation of the groups in general allies 
Florissant on the whole with the upper eocene rather than with the 
lower miocene of Europe. 
Of extinet genera there have certainly been proposed a very large 
number for the European Araneidae, more than half the genera to which 
the species have been referred having been described as new and pe- 
culiar to tertiary times; these genera include about two-fifths of the 
species. Among the genera are some remarkable forms, such as Archaea 
and Mizalia, each of which is considered by Thorell and others as repre- 
senting a distinct family. Two only of the thirteen genera into which 
the American species fall are new, and to them are referred 7 of the 32 
species. Other genera, not before recognized in a fossil state, occur- 
ring in American strata are Titanoeca, Tetrognatha, and Nephila. To 
enter into brief particulars on this point, 71 genera of Araneidae are now 
known from the tertiaries, 66 from Europe and 13 from America, 8 being 
common to both; of these genera, 37 are accounted extinct, 35 from 
Europe and 2 from America, none of these being found in both coun- 
tries. As may be supposed, the European genera are largely composed 
of amber species, no less than 52, including 32 extinct genera, being con- 
fined to amber deposits, which also contain other genera in common 
with the stratified deposits. 
To review rapidly the different forms of spiders found at Florissant, 
we may first call attention to a new genus, Parattus, to which the three 
species of Attides are referred; the fossil species of this family hitherto 
recorded are all confined to amber excepting one, Attoides eresiformis 
from Aix; one of the amber genera is Gorgopis, including nearly half the 
12 species, a genus allied to Phidippus, richly represented to-day in 
North America; and it is interesting to find that Parattus, although a 
very aberrant form, with four large eyes instead of two, is more nearly 
related to Gorgopis than to any other genus. All but four of the 21 
fossil Thomisinae thus far described come from amber, among them one 
Thomisus; Oeningen also furnishes two species of this genus and Rott 
another, with a Xysticus; three species of Thomisus come from Floris- 
sant. The three families of Tubitelariae which are represented in the 
European and American strata are the ones most abundant at the pres- 
ent day. The fossil Dysderides of Europe (16 sp.) are all from amber, and 
include 8 species of Segestria, into which the single species from Floris- 
sant falls. The Drassides are very abundant in the European amber, 
and our own fauna shows four species of Clubiona and one of Anyphaena, 
