258 
PACIFIC SCIENCE, Vol. XXII, April 1968 
TABLE 3 
Morphometric Ratios of Cyclops kolensis from Different Populations 
POPULATIONS 
RAMUS 
LENGTH 
TO WIDTH 
SEGMENT 3 
ENDOPOD 
LEG 4 
LENGTH : 
WIDTH 
INNER 
TERMINAL 
seta : 
OUTER 
TERMINAL 
SETA 
INNER 
TERMINAL 
SETA : 
RAMUS 
INNER 
TERMINAL 
SPINE 
ENDOPOD 
LEG 4 : 
OUTER 
TERMINAL 
SPINE 
SEGMENT 3 
ENDOPOD 
LEG 4 
LENGTH : 
INNER 
SPINE 
LENGTH 
Pt. Barrow, Alaska 
4.6 4.1-5. 1 
3.0 2.9-3. 1 
1.2 1. 2-1.4 
.8 .7- .9 
1.9 1.7-2. 2 
1.0 .96-1.1 
St. Matthew Island 809 
4.1 4. 1-4.2 
2.3 2. 1-2.6 
1.4 .8-2.1 
.9 .7-1.2 
1.6 1. 3-1.9 
.9 .8 -1.1 
St. Matthew Island 81 4 
St. Matthew Island 
3.9 3. 6-4. 3 
2.2 1 .9-2.4 
1.3 1.0-1. 7 
.8 .6- .9 
2.3 1. 8-2.8 
.9 .8 -1.1 
combined 
3.9 3- 7-4. 2 
2.2 1 .9-2.4 
1.3 .9-1.6 
.8 .7- .9 
1.9 1.4-2. 5 
.9 .7 -1.6 
Siberia (Rylov 1948) 
5.0 3. 5-6.6 
2.8 2. 1-3.6 
1.4 1. 1-1.9 
.7 .5-1.0 
2.6 1.6-4. 3 
1.0 .7 -1.4 
Germany (Herbst 1955) 
Alaska (Marsh’s material 
5.3 5. 0-5. 6 
3.0 2.9-3. 2 
1.6 1. 5-1.7 
1.1 .9-1-3 
2.6 2. 4-2.7 
1.0 .9 -1.1 
U.S.N.M.) 
Poland (Kozminski’s 
4.8 4.2-5. 8 
3.2 2. 7-4.0 
1.4 1. 3-1.6 
.7 .6- .8 
2.3 1.8-2. 9 
.9 .8 -1.1 
material U.S.N.M.) 
5.4 4. 0-6. 9 
3.7 
1.6 1. 3-1.9 
1.2 1.0-1. 5 
2.0 
1.1 
segment of endopod 4 (Pt. Barrow ca. equal 
marked C. 
strenuus, 
but on the 
basis of a 
to St. Matthew 809) 
and outer 
spine (St. 
2, 3, 3, 3 spine formula are most likely C. kolensis. 
Matthew 809, the longest). Quotients of inner 
Slide 4418 
labeled C. 
strenuus is 
C. scutifer. 
seta — outer seta, endopod -y- inner 
spine, and 
Slides 4332, 4335 and 4337 are 
labeled C. 
for the Alaskan population inner seta -y- ramus 
indicate no allometry (Fig. 19, panels C, F, D) . 
Means of different measurements are com- 
pared in Table 4. The two St. Matthew popula- 
tions differed at a level of .001 in lengths of 
furcal rami, of endopod segment 3 on leg IV, 
and of outer spine on the segment. The Pt. 
Barrow animals were most like those of St. 
Matthew 809 and differed greatly (five measure- 
ments at .001 level and one at .05 level) from 
St. Matthew 814. Comparing Pt. Barrow ani- 
mals with combined St. Matthew samples 
showed an intermediate condition. 
COMPARISON OF PRESENT SPECIMENS 
WITH MARSH’S MATERIAL 
The U. S. National Museum loaned the Cape 
Collinson specimens for examination. In all, 
nine slides labeled by C. D. Marsh and a small 
vial of whole specimens in alcohol were avail- 
able. Slide 4438 (Marsh’s number) contained 
six whole females, the other slides held dis- 
sected animals. Slides 4330 and 4334 are prob- 
ably Cyclops venustoides Coker, although 
labeled C. vicinus. Slides 4331 and 4336 are 
vicinus . The least distorted animals on the slides 
were measured (Table 2). 
The alcohol-preserved specimens were con- 
siderably distorted and covered with ecto-com- 
mensal stalked protozoans. The form of the 
thoracic segments agrees with the descriptions 
of C. kolensis but not of C. vicinus. 
The ratios derived from measurements in 
Table 2 compare favorably with ratios of other 
Alaskan populations (Table 3). The evidence 
available indicates that Marsh’s specimens 
should be referred to C. kolensis Lilljeborg. Al- 
though all of the Alaskan populations do exhibit 
some individual characteristics as a group they 
differ little from one another. 
COMPARISON OF ALASKAN POPULATIONS WITH 
OTHERS DESCRIBED IN THE LITERATURE 
Rylov (1948) and Herbst (1955) measured 
various body parts of C. kolensis from Siberia 
and Germany (Grosser and Ploner See). Their 
measurements have been included in Table 2. 
In comparing ratios (Table 3 and Fig. 19) the 
Siberian and German animals do not exhibit 
constant patterns in relation to the other popula- 
