288 Wisconsin Academy of Sciences, Arts, and Letters. 
Table II.—Variations in form and size of C. americanus. 
Coll, of C. D. 
Marsh. All 
mature $ . 
Form and length 
out. ter. spine of 
furca. 
Length of 
furca. 
Width of furca, 
1. terminal, 
2. base. 
Armature ter. 
joint 4th foot. 
No. 1500. 
Jackson, Miss 
Very large, Mar., 
Moderately slender, 
apex broken. 
.08 mm. 
. 19 mm. 
1. .04 mm. 
2. ,06 mm. 
Inner ex. 1 seta, 
br. ap. 2 sp. 
’93. 
No. 1502. (1) 
Arcade, May, ’91, 
Slender. .04 mm. 
.052 mm. 
1. .015 mm. 
2. .025 mm. 
br. Lost. 
small. 
No. 1502. (2) 
Same coll, as 1502. 
Cl) 
.07 mm. 
Moderately slen¬ 
der. 
.132 mm. 
1. .0325 mm. 
2. .055 mm. 
Inner ex. 1 seta, 
br. ap. 2 sp. 
No. 1501. 
Dakin farm. 
May, ’93. 
.09 mm. 
Moderately slen¬ 
der. 
.185 mm. 
1. .0325 mm. 
2. .0625 mm. 
Inner ex. 1 seta, 
br. ap. 2 sp. 
No. 1001. 
Pool near Elcho 
Station, Aug., 
.0625 mm. 
Slightly thickened 
toward apex. 
.14 mm. 
1. 'iOSmm. 
2. .045 mm. 
Inner ex. 1 seta, 
br. ap. 2 sp. 
’87. 
No. 885. 
Pond, Grrinnell, 
.06 mm. 
Very slender. 
.11 mm. 
1. .035 mm. 
2. .0425 mm. 
Inner ex. 1 seta, 
br. ap. 2 sp. 
la. 
No. 883. 
Lincoln, Neb. 
.0875 mm. 
Very slender. 
.155 mm. 
1. ,03 mm. 
2. ,05 mm. 
Inner ex. 1 seta, 
br. ap. 2 sp. 
No. 882. 
Lincoln, Neb. 
.085 mm. 
Very slender. 
.17 mm. 
1. .03 mm. 
2. .05„mm. 
Inner ex. 1 seta, 
br. ap. 2 sp. 
No. 565. 
Pool near Arcade. 
.0575 mm. 
Tapering, not slen¬ 
der. 
.1275 mm. 
1. 03 mm. 
2. .045 mm. 
Inner ex. 1 seta, 
br. ap 2 sp. 
No. 425. 
Pond, Lyman 
Farm, May, ’82. 
.075 mm. 
Slender. 
.145 mm. 
1. ,03 mm. 
2. .0475 mm. 
Inner ex. 1 seta, 
br. ap. 2 sp. 
No. 784. 
. 7 mm. 
Moderately slen¬ 
der. 
.125 mm. 
1. .0275 mm. 
2. .045 mm, 
Inner ex. 1 seta, 
br. ap. 2 sp. 
