﻿NORTH AMERICAN NOTOSTRACA — LINDER 



23 



Though the occurrence of spiral growth and of incomplete body- 

 rings has no significance at all for the taxonomy of the Notostraca, I 

 think that both these kinds of abnormalities are of considerable 

 interest, and I hope that others who come across cases of spiral 

 growth will publish their findings. 



THE TELSON AND SUPRA-ANAL PLATE 



The tclson is heavily chitinized and is thus very little subject to the 

 influence of the preservation fluid. Disregarding the supra-anal 

 plate, the telson is very short in L. couesii and L. packardi, and un- 

 usually long in the new species and variety of Lepidurus (figs. 9, 10, 



Figure 8. — Dorsal view of telson of a female of Apus cancriformis (Bosc) from Safi, French 



Morocco (U.S.N.M.), X 23. 



Figure 9. — Dorsal view of telson of a male of Lepidurus couesii Packard (Stockholm Mus.), 



X 13. 



