6. C. mexicanus.[51] Plumage highly lustrous, blended. Soft burnished steel-blue, changing to violet on the crown, and with a greenish cast on lower parts. Wing, 9.00; tail, 6.50; culmen, 1.60; tarsus, 1.20; middle toe, 1.10. Wing-formula, 4, 3, 5. First quill very much longer than tenth. _Hab._ Western Mexico (Mazatlan, etc.). B. Angle of mouth naked—West Indian Crows. _a._ Tarsus much shorter than the bill. 7. C. nasicus.[52] Nostrils scarcely concealed by the short nasal bristles. Entirely violaceous-black, the feathers smoky-gray beneath the surface. Wing, 11.00; tail, 7.75; culmen, 2.45; depth of bill, .80; tarsus, 1.95; middle toe, 1.50; graduation of tail about 1.00; wing-formula, 4, 3, 5, 6, 2; first quill shortest. _Hab._ Cuba. 8. C. leucognaphalus.[53] Nostrils well concealed by the longer, but rather scant, nasal bristles. Entirely violaceous-black, the feathers of the neck all round, breast and sides, pure white below the surface. Wing, 12.50; tail, 9.00; culmen, 2.45; depth of bill, .95; tarsus, 2.15; middle toe, 1.50; graduation of tail about 1.25. Wing-formula, 4, 5, 3, 6, 2; first quill much the shortest. _Hab._ Porto Rico. _b._ Tarsus about equal to bill. 9. C. jamaicensis.[54] Nostrils just covered by the short but dense tuft of nasal bristles. Entirely dark sooty-plumbeous, inclining to black on the head, wings, and tail, where is a very faint violaceous gloss. Wing, 9.50; tail, 6.50; culmen, 2.00; depth of bill, 1.70; tarsus, 2.05; middle toe, 1.35; graduation of tail, about .60. Wing-formula, 5, 4, 3, 6, 2; first shortest. _Hab._ Jamaica. [50] The measurements given are of a California specimen, in order the better to show the great distinction to be made between this species and _caurinus_, which is probably not found in California, being a more northern species, and having the coast of Washington Territory, or perhaps Oregon, as about its southern limit. [51] _C. mexicanus_, GMEL. Syst. Nat. p. 375. This species is perfectly distinct from all the others. The plumage has a silky blended character, and very high lustre, almost exactly as in the larger Grakles (_Quiscalus major_, etc.). [52] _C. nasicus_, TEMM. Pl. Col. 413.—GUNDL. Rev. y Catal. de las Aves de Cuba., 1865, 290. _Corvus americanus_, LEMB. Aves de Cuba, 1830, 65. _Hab._ Cuba. [53] _C. leucognaphalus_, DAUD. Tr. d’Orn. II, 231.—SALLÉ, P. Z. S. 1857, 232.—BRYANT, Pr. Bost. Soc. 1866, XI, 94. _Hab._ Porto Rico and Santo Domingo.