This genus is very close indeed to the last, differing principally in its smaller, more pointed, bill, which has, however, the culmen gently curved throughout in the same manner.
Key to Species and Subspecies.
A. Crown black streaked with white.
a. Throat blackish grey, mottled white S. nigriceps nigriceps, p. 264..
b. Throat deep grey or black S. n. coltarti, p. 265.
c. Throat ashy-grey S. n. davisoni, p. 265.
B. Crown golden-yellow streaked with black.
d. A black streak through eye.
a1. Upper parts olive-yellow S. chrysaea chrysaea, p. 265.
b1 Upper parts dark olive-green.
a2. Under parts bright yellow .. S. c. assimilis, p. 267.
b2. Under parts dull yellow .... S. c. chrysops, p. 267.
e. No black streak through eye S, c. binghami, p. 266.