EXPLANATION OF PLATE 10. 



Lamps of the Mackenzip: River. 



Fig. 1. Section, outline, and front view of small lamp witli bitid bridge. 



(Cat. No. 2071, U.S.N.M. Mackenzie River, Canada. Collected by R. MacFarlane.) 



Fig. 2. Outline, section, and front view of small lamp. 



(Cat. No. 1109, U.S.N.M. Mackenzie River, Canada. Collected by R. MacFarlane.) 



