AKT. 18 SYNOPSIS OF CALANOID CRUSTACEA MARSH 21 



Length : According to Lilljeborg : Female, about 2 mm, male, about 

 1.7 mm; according to Schacht: Female, 2 mm to 2.5 mm, male, 1.7 

 mm to 2.1 mm. The author has made a number of measurements ; of 

 these the largest average was in collections from Hope, Idaho; the 

 females measured 2.02 mm, the males 1.76 mm. In Tsiltcoos Lake, 

 Oreg., the females averaged 1.32 mm and the males 1.27 mm. 



Occurrence. — The original description was from material collected 

 in Echo Lake and Lake Tahoe in California. Forbes found it in 

 Swan Lake and Flathead Lake, Mont. Schacht also reported it from 

 Gambles Lake and Lake Pend Oreille, Idaho ; Lake Tahkenitch and 

 Tsiltcoos Lake, Oreg.; and Lake Union and Lake Washington, Wash. 

 Kemmerer, Bovard, and Boorman (1924) found it in many lakes in 

 Washington and in Bear Lake, Idaho. It was found in collections 

 made by E. M. Ball on Afognak Island, Alaska. T. L. Thacker has 

 sent material from Lake Schkam and Kawakawa Lake, British Co- 

 lumbia, in which this species was found. The author found it in ma- 

 terial collected by Dr. H. B. Ward, from a number of small lakes near 

 Lake Tahoe, and has collected it in Stanislaus National Forest, Calif., 

 and in Lake Chelan, Wash. An immature Epischura was found in 

 Lake Helen on Mount Lassen, Calif., and in a pond at an elevation 

 of 1,000 feet near Baldwin, Colo. It was impossible to identify 

 this material but it probably would be this species. It will be seen 

 that the distribution is pretty well limited to the Pacific region, the 

 most eastern point being Bear Lake, Idaho, if we disregard the possi- 

 ble location in Colorado. It has not been found much south of the 

 Lake Tahoe region but extends north into Alaska. 



Remarks. — The original description by Lilljeborg is correct, but 

 his figure of the male abdomen is misleading; from a certain angle 

 it is correct as shown by the similar drawing from the ventral side. 

 (PI. 12, fig. 1.) Plate 11, Figure 3, however, gives a more accurate 

 idea of its form. The figure by Forbes (1893) was in the main correct. 

 Schacht stated that the appendage near the outer distal angle of the 

 first segment of the female fifth foot is " correctly drawn by Lillje- 

 borg as a seta, while Forbes's figure represents it as spine-like." This 

 appendage seems to vary, sometimes being a seta and sometimes a 

 spine. In material from Lake Tahoe it was a spine. 



EPISCHURA NORDENSKIOLDI Lilljeborg 



Plate 12, Figures 2-6 



Epischura nordenskioldi Lilljeboeg. in de Guenie and Richard, 1889, p. 146, 

 pi. 1, fig. 36, pi. 2, figs. 15, 2.3.— Herrick and Turner, 1895, p. 85, pi. 11, figs. 

 2, 5, 9.— Giesbrecht and Schmeil. 189S, p. 183.— Schacht, 1898, p. 252.— 

 TOLLINGER, 1911, p. 153, fig. N*.— Kiefer, 1931, p. 583, figs. 1, 2. 



Epischura nevadensis Wilson, 1932, pp. 115-117. fig. 77. 



