1951] 
Christiansen — Alaskan Collembola 
135 
Segmental ratios: 
(abdominal segment 4—10) 
total cephalic thoracic segment 
antenna diagonal 12 3 
mean ratio 
13.4 
18.1 4.4 8.8 
10.7 
average deviation 
.8 
1.3 .4 .6 
.7 
abdominal segment 
furcula 
third 
1 
2 3 4 5 
6 
unguis 
mean ratio 
9.7 
9.5 8.8 10 5.9 
5.3 
11.6 
3.5 
average deviation 
.4 
.5 .3 X .3 
.5 
.8 
.3 
(antennal segment 4=10) 
antennal segments 
12 3 4 
mean ratio 6.3 6.8 6.7 10 
average deviation .9 .8 .7 X 
(macro— 10) 
manubrium dens mucro 
mean ratio 32 25 10 
average deviation 4 3 X 
(unguis=10) 
unguis 
mean ratio 10 
average deviation X 
unguiculus 
4.3 
.2 
Type locality: Point Barrow, Alaska, June 1949, Neal 
A. Weber, collector. The holotype and forty paratypes are 
being deposited in the United States National Museum, 
Washington, D. C. A series of twenty paratypes is being 
deposited in the Museum of Comparative Zoology, Cam- 
bridge, Massachusetts. 
Anurida hammeri, n. sp. 
(PI. 12, figs. 1-13) 
Holotype. Color white, pigment completely lacking. 
Clothing of scattered straight stout setae of varying lengths. 
Body about four and one-half times as long as wide, deeply 
