General Notes. " 127 



shield, together with the prominent vertical horn, are cast, the bird then 

 becoming C. " stickle yi." In Ciceronia micrnceros, a similar but much 

 smaller knob is moulted, when the bird becomes C. "pusilla." The 

 change is most remai'kable in Simorhynchus, in which, apparently, not 

 only the conspicuous rictal plate, and greatly enlarged basal portion of the 

 mandible, but also, apparently, the entire sheath of the bill, are moulted, 

 the species in this stage being ..S. " tetraculus " (Pall.). Unfortunately, I 

 have not been able to examine undoubted winter specimens oi' Phaleris 

 psittacula, but as the bill is exceedingly simple (there being no accessory 

 pieces) in this species, during the breeding season, it is quite jiossible, 

 though hardly probable, that no change takes place. 



It is a somewhat singular, and perhaps important circumstance, that in 

 nearly every species in which this singular transformation of the bill takes 

 place there is little if any change in the plumage, the colors and orna- 

 mental plumes of the breeding season being worn all the year round. On 

 the other hand, in Mergulus alle, and the species of Synthlihorhawphus, 

 Brachyrhamplius, Uria, and Lomvia, the bill is simple and entirely devoid 

 of deciduous elements, while the seasonal change of plumage is very 

 marked. This, however, is also the case in Alca impennis and Utamania 

 torda, in which there is an apparently deciduous basal maxillary lamina. 



Besides the doubtful case of Phaleris, we are not sure as to Ptycorham- 

 phus aleuticus. This has the bill moi-e or less corrugated at the base, and 

 this corrugation is undoubtedly more conspicuous in summer than in 

 winter specimens. Both this species and Phaleris psittacula have an 

 unvarying plumage, and on this account we are disposed to refer them to 

 the group having a greater or less portion of the bill deciduous, without, 

 however, having any better reason for doing so. — Robkkt Ridgway, 

 Washington, D. C. 



[Since the above was put in type, I find that in the announcement of 

 the discoveries in question I have been anticipated by Dr. Louis Bureau, 

 who treats of the subject in detail in a very important paper, entitled, 

 " Recherches sur la Mue du Bee des Oiseaux de la Famille des Mor- 

 monides," published in the " Bulletin de la Societe Zoologique de Fi-ance " 

 (December, 1879, pp. 1-68). The species treated by Dr. Bureau are 

 Fratercida arctica (including " des differentes formes que revet le Frater- 

 cula arctica suivant les regions qu'il habite "), F. corniculata, Lunda cir- 

 rhata, " Chimerina cornuta " {= Ceratorhina monocerata) , " Omhria " psitta- 

 cula, Simorhynchus cristatellus, and S. kamtschaticiis. In Phaleris psittacula 

 it seems that the nasal shield (" cuirasse nasale ") alone is deciduous. — 

 R. R.] 



Further Light on the Moult of the Bill in certain Mor- 

 MONiD^.* — When M. Bureau announced his great discovery, that the 



* Recherches sur la Mue du Bee des Oiseaux de la Famille des Mormonides 

 par le Docteur Louis Bureau. Extract du Bull, de la Soc. Zool. de France. 

 Paris, 1879. 8vo. Pp. 68, pll. vi, and a map. 



