_Pennula_ Dole, Hawaiian Alman. 1879 p. 54 (Reprint in Ibis 1880 p.
241).
I believe that the genus _Pennula_ should be placed near _Porzanula_, but
its wings are softer, the rectrices are next to invisible, but can be felt,
as they have stiff shafts and are about 13 mm. long, though being entirely
hidden by the soft tail-coverts. The tibia is bare for about 7 mm., the
metatarsus covered in front with nearly a dozen transverse, very distinct
scales, and distinctly reticulated behind. The bill much as in
_Poliolimnas_ and _Porzanula_.
Two species can be recognized: _Pennula millsi_, with a uniform upper
surface, and _Pennula sandwichensis_, with a distinctly spotted upper side.
Both forms are now extinct.