A review of the Notostraca

Abstract

This paper reviews the known species of Notostraca on the basis of a large collection of museum material and on information from the literature. The genus Triops is reduced to four, and the genus Lepidurus to five species. The species of T1'iops are separated on the armature of the telson and on the presence or absence of a second ma.xilla; in each species there is considerable variation in the segment number, and in the many structures whose variation is shown to be correlated with this number. The segment number is more constant in Lepidurus and fewer structures are correlated with its variation; this genus appears to fall into two groups, as Linder (1952) suggested, on the basis of the segment number. A new species of Lepidurus is described from Russia. In addition to the analysis of the validity of the systematic characters from work on preserved specimens, evidence derived from the growth and development of living animals, their cytology, their reproduction and their protein specificity are also considered.