Skinner, Ernest B. (ed.) / Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume XIV, Part I (1902)
Variations in form and size of Cyclops brevispinosus Herrick and Cyclops americanus marsh, pp. -Plate XXXIII ff.
VARIATIONS IN FORM AND SIZE OF CYCLOPS BREVI- SPINOSUS HERRICK AND CYCLOPS AMERICANUS MARSH. BY HARRIET LEHMANN. This investigation was undertaken under the direction of Professor C. Dwight Marsh of Ripon College, to determine the extent of variation. in C. brevispinosus Herrick and C. amer- icanius Marsh, particularly with reference to the question of specific distinction between these forms in the form and meas- urements of the, furca., and the outer terminal spine of the furca, and in the armature of the terminal joint of the inner ramus of the fourth swimming foot. The results obtained cannot, however, be considered con- clusive, since the number of specimens examined was insuffi- cie~nt to permit- exact- conclusions. The variations were also found to be so wide in a small number of specimens that even greater variation might be possible in a large number. Different investigators do not agree as to the characters of the genus Cyclops important for specific distinctiom Brady, '78, gives, "the characters of the first antennae and fifth pair of feet As offering subsidiary characters, the spinous armature of the swimming feet, together with the tail segments and setae, are also. important." Schmeil, '92, says, "Die sichersten und einfachsten Erkennungsmerkmale sind das rudimentiire Fiis- schen mnd der Bau des Receptaculum, seminis. * * *Die Anzahl der Borsten und Dornen ist fur die Individuen einer Art durchaus nicht konstant, so das allien heiraufgegriindete Arten hinfiallig werden. Hiermit soll natiirlich nicht ausge- sprochen sein dass die Beriicksichtigung der Bewehrung der U FRNF,-W- -'VW-ImmwW.-ww -, -wwI .1 I 1-1 i
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