Marsh — North American Species of Cyclops. 1097 



The form of the receptaculum seminis is shown in the figure, 

 (PI. LXXVIII, fig. 9). 



The egg-sacs are elongate and stand out from the abdomen. 

 The number of eggs is variable. 



The size is variable, commonly running between .8 and 1.25 

 mm., but greater extremes are not unusual. 



The species has been found so widely distributed that it 

 may be considered cosmopolitan. 



It is convenient to use the varietal names montanus Brady 

 and elegans Herrick in speaking of the extreme forms. Mon~ 

 tanus is small, dark colored with short and stout furca, and 

 "with few eggs in the egg sacs. Elegans is larger, slender, with 

 long and slender furcae, and numerous eggs in the egg sacs. 

 As indicated by me in a former publication (Marsh '92) mon- 

 ianus is more common in pools and elegans in lakes. Elegans 

 may be considered as limnetic and montanus as litoral. There 

 are exceptions to this distribution, however, for elegans may 

 be found in shallow waters, and in collections in the southern 

 states it is not unusual to find both forms in the same col- 

 lection. 



CYCLOPS PRASINUS Fischer. 



Plate LXXVIII, figs. 1, 2, 3 and 10. 



1860. Cyclops prasinus Fischer, p. 652, pi. XX, figs. 19-26a. 

 1871. " longicornis Vernet, p. 44, fig. 3. 



1882. " fluviatilis Herrick, p. 231, pi. VIII, figs. 1-9. 



1883. " magnoctavus Cragin, p. 5, pi. II, figs. 14-23. 



1884. " fluviatilis Herrick, p. 159, pi. Q 5 , figs. 1-9. 



1886. " pentagonus Vosseler, p. 191, pi. V, figs. 32-37, pi. VI, figs. 



11 and 12. 



1887. " pentagonus var. vichyensis Richard, p. 162. 



1887. " fluviatilis Herrick, p. 15. 



1888. " prasinus Richard, p. 65. 



1891. " magnoctavus Brady, p. 19, figs. 1-4. 



1891. " pentagonus Schmeil, p. 31. 



1891. " " Blanchard & Richard, p. 515. 



1891. " " Richard, p. 233, pi. VI, fig. 8. 



1892. " prasinus Schmeil, p. 150, pi. V, figs. 1-5. 



1893. " fluviatilis Marsh, p. 214, pi. V, figs. 14 and 15, pi. VI, fig. 1. 

 1895 . ' ' fluviatilis Marsh, p. 18. 



1895. " fluviatilis Herrick and Turner, p. 114, pi. XXVI, figs. 1-8, 



pi. XXX, figs. 1. 



