520 



THE DIVING BIRDS — PYGOPODES. 



compressed vertical process of the nasal shield, characteristic of the bree(liiij,'-sea8on. When the 

 latter is cast, the upper outline of the cere is nearly straight, and depressed decidedly helow the 

 level of the base of the culnien. Head ornamented by four (two on each side) longitudinal series 

 of filamentous white feathers. Plumage dull-grayish dusky above, whitish below, the under side 

 of the head and neck brownish gray. 



V, vionocerata, summer adult. 



C. munocerata, winter adult. 



Of this remarkable genus but one species is known ; this having given ornithcdogi.sts much 

 trouble before the deciduous character of the nasal horn and mandibular process was fully under- 

 stood ; the same species in winter plumage, with these appendages absent, being referred to a 

 different genus Q^ Sugnmtorhina"). 



Cerorh]mcha monocerata. 



THE HOBN-BILLED AITK. 



Akfi monocerata, Pall. Zoog. l!osso-As. II. 1826, 362, no. 414. 



Ccrorhina mmiocerala, Cass, in Build's H. N. Am. 1858, 905. — BAiisn, Cat. N. Am. B. IS.IO, no. "17. 



Vrrntorhyncha monocerata, CouKs, Vi: Ac. Nnt. Sci. Philnd. 1868, 28, ligs. 1, 2. 



Ceratorhina mmioccrata, Coues, Key, 1872, 341 ; Check List, 1873, no. 620 ; ed. 2, 1882, no. 857. — 



Kinow. Norn. N. Am. 15. 1881, no. 620. 

 Phalcris crrorhi/nea, Boxai'. Zool. Jouin. 1827, 53. 

 Cerorhinea occidentalis, BoN'Ai'. Ann. Lye. N. Y. (Synop. N. Am. B. ) IV. 1828, 428. — Nltt. Man. 



II. 1834, 538. 

 Ceratorhina occidentalis, Am. Orn. Biog. V. 1839, 104, pi. 402, fig. 5. 

 Uria occidentalis. Am. B. Am. VII. 1844, 304, pi. 471. 



Cerorhina orientalis, Bkandt, Bull. Ac. St. Pctcrsb. II. 1837, 348 (lapsus calami for occidental is i.). 

 Chimcrina comuta, Esciiscuoltz, Zool. Atl. III. 1829, 2, pi. 12. 

 Ccrorhina Sucklei/i, Cass, in Baird's B. N. Am. 1858, 906 (adult without knob on bill). — Baiuu, 



Cat. N. Am. B. 1859, no. 718. 

 Sagtnalorhina Suckleyi, CouEs, Pr. Ac Nat. Sci. Philad. 1868, 32, figs. 4, 5 (bill). '^ 



Tlie Horn-hilled Guillemot, Cass. & Baiud, 11. c. 



Had. Coasts and islands of the North Pacific, breeding as far south as California (Farallon 

 Islands) and Northern Japan ; in winter, as far as Lower California. 



Sp. Char. Adult, breeding jihtmage : Entire njiper ]>arts dull brownish black, tlie feathers some- 

 times with paler or grayish brown tips ; lateral and under parts of liead and neck, jiiguhuu, and 



