NO. 3534 EURYTEMORA WILSON AND TASH 563 



In 1961, collections were made in Lake 4 from April to August 7. 

 No specimens of E. arctica were taken in open water until July 6. 

 On July 13 and two subsequent dates, both open water and the beds 

 of rooted vegetation (mostly Arctophila fulva) were sampled, the 

 latter by hand-dipping a net. The samples from the two areas are 

 not quantitatively comparable, but it is believed that due to the 

 difficulty of maneuvering both the boat and the net in the thick 

 vegetation,only a small part of the popidationof thelatter was sampled. 



Summary of number of specimens of copepodid stages (C) collected 

 on four dates of 1961: 



ope7i water vegetation 



CIV CV? C Vd^ CIV CV9 CVd^ 



July 6 1 not collected 



July 1.3 1 12 5 



August 2 1 29 22 



August 7 13 6 5 



Total specimens 7 70 



Ponds and pools near lake 4. — The poorl}^ drained Carex marsh 

 surrounding Lake 4 has numerous ponds and pools of varying size 

 and permanence. In 1960, E. arctica was collected from 3 of those 

 having a heavy growth of vegetation around the perimeter or partially 

 covering the water. Collection records: (1) Pond (estimated area, 

 500 square meters; maximum depth about 1 meter; permanent), 

 July 7: 1 C III, 2 C V9; occurring with Heterocope septentrionalis and 

 Diaptomus arcticus. (2) Pool (estimated area, 83 square meters; 

 maximum depth about 1 meter), September 8: 1 C VI9 with ovisac, 

 15 C VI cf, some with spermatophores attached to apex of leg 5. 

 (3) Pool (estimated area, 10 square meters; maximum depth about 1 

 meter), September 8: 2 C Vl9 (1 with mcomplete ovisac), 6 C VI cf". 



Lake 3 (68°11'09" N., 165°42'02'' W.; surface area, 1.8 hectares; 

 maximum depth, about 1.52 meters). — In 1 of 2 samples collected 

 on different dates from open water, August 19, 1960: 2 C Vcf . On 

 July 17, 1959, 4 specimens presumed to be this species (C III, C IV) 

 were collected by D. Hilliard from 2 separate pools in the vicinity of 

 Lake 3. 



Lake 8 (68°11'06" N., 165°42'04'' W.; area 0.03 hectares; max- 

 imum depth about 1.52 meters). — In 1 of 2 samples collected on 

 different dates from open water, August 19, 1960: 1 C VcT, 1 C Vl9. 



In 1961, no specimens occurred in collections made on one occasion 

 from open water and weeds of Lakes 3 and 8. 



Lake 9 (68°14'08" N., 165°34'09" W.; about 4 miles northeast of 

 Lake 4, in Saligvik Valley ; outlet to creek tributary to Kukpuk River; 

 surface area about 12 hectares; maxim imi depth unknown but prob- 



