PLATE X. 
. NavicuLa aspeRA, Ehrenberg. a, S. V., typical; 
4, short var.; c, M.V. 
Navicuta Cuepsypra, Donkin. a,8. V.; 6,M. V. 
Navicuta retusa, De Brébisson. a,8.V.; 6,M.V. 
NavicuLa crucirormis, Donkin. S. V. 
. NavicuLa REcTANGULATA, Gregory. 8. V.; the 
M.V.of this species and of N. cruciformis closely 
resembles that of N. Trevelyana. 
. Navicuta Trevetyana, Donkin. a,8.V.; b,M.Y¥. 
Navicuta Humiuis, Donkin. a,S.V.; 5, M. V. 
