[Illustration: PLATE XXXVII. 1. Quiscalus purpureus. ♂ Pa., 1363. 2. ” aglæus. ♂ Fla., 10342. 3. Corvus caurinus. ♂ Sitka, 46662. 4. ” mexicanus. ♂ Mazatlan, 52802. 5. ” americanus. ♂ D. C. 6. ” carnivorus. ♀ Neb., 4546. 7. ” ossifragus. D. C., 4515. 8. ” cryptoleucus. Texas, 46798. 9. ” floridanus. Fla., 10374.] Species and Varieties. RAVENS. Feathers of the chin and throat stiffened, elongated, narrow and lanceolate, with their outlines very distinct. 1. C. corax var. carnivorus. Length about 25.00; wing, 17.00; tail, 10.00; graduation of tail, 1.60 to 2.40. Feathers of the neck and breast light gray beneath surface. _Hab._ Whole of North America; Guatemala and Mexico. Rare in Eastern United States. 2. C. cryptoleucus. Length about 21.00; wing, 14.00; tail, 8.50; graduation of tail, about 1.25. Feathers of neck and breast snowy-white beneath surface. _Hab._ Llano Estacado, or Staked Plain of Texas; Arizona; Colorado. CROWS. Feathers of chin and throat soft, short, broad, obtuse, and with their webs blended. A. Angle of mouth feathered—North American Crows. _a._ Tarsus longer than the bill. First quill not longer than tenth. 3. C. americanus. The gloss of the plumage purplish-violet, and hardly perceptible on head and neck, middle toe and claw rather shorter than tarsus, measured from beginning of scutellæ. Wing, 12.25; tail, 7.20; culmen, 1.85; tarsus, 2.00; middle toe, 1.45; wing-formula, 4, 3, 5, 6, 2; first quill equal to tenth. _Hab._ North America generally var. _americanus_.[50] Wing, 12.50; tail, 7.20; culmen, 2.10; tarsus, 2.30; middle toe, 1.60. Wing-formula? (moulting). _Hab._ South Florida var. _floridanus_. 4. C. ossifragus. The gloss of plumage violaceous-blue, almost green on the head, neck, and breast, where very perceptible. Middle toe and claw longer than tarsus, as above. Wing, 10.50; tail, 6.50; culmen, 1.55; tarsus, 1.65; middle toe, 1.35. Wing-formula, 4, 3, 5; first quill slightly shorter than tenth. _Hab._ Atlantic Coast of the United States. _b._ Tarsus shorter than the bill. First quill longer than tenth. 5. C. caurinus. Gloss of the plumage as in _americanus_, but deeper. Wing, 10.50; tail, 6.40; culmen, 1.95; tarsus, 1.70; middle toe, 1.25. Wing-formula, 4, 3, 5. _Hab._ Northwestern coast of North America.