480 ANNUAL HECOKD OF SCIENCE AND INDUSTRY. 



like excrescence at the base of the upper mandible of the pel- 

 ican was characteristic of the breeding season, and that when 

 that season had passed, the bird cast the excrescence, and 

 appeared without it till the approach of the next nuptials. 

 The fact of the deciduous nature and periodical recurrence 

 of corneous elements in the bills of birds does not appear pre- 

 viously to have been recorded in scientific literature, and the 

 announcement thus signalized was of unusual interest. 



C5 



A moult of corneous elements of the bill, analogous to that 

 in the pelican, but much more comprehensive, was shown last 

 year, by M. Bureau, to take place in the common puffin \Fva- 

 tercula arctica) of Europe. Differences in the bill had long 

 before been noticed in this type, but had been attributed to 

 age or specific differentiation. M. Bureau's scepticism as to 

 the verity of these views was excited by observations on the 

 puffins inhabiting islands of the French province of Brittany ; 

 and finally he w r as led to the knowledge that the differences 

 signalized were the result of a regular seasonal moult of con- 

 stituents of the bill; and that the brilliantly colored one was 

 characteristic of the season of love, while the plainer was the 

 feature of the season of rest from amorous labor. As the 

 discovery is of more than usual interest, a somewhat detailed 

 notice is in place. 



The bill of the puffin may be distinguished into two parts, 

 an anterior and a posterior, which, on the upper mandible, are 

 nearly equal, and narrow towards the forehead ; while on the 

 lower mandible they correspond at the commissure, but dif- 

 fer in relative proportions. The anterior of these has a sin- 

 gle persistent sheath, and it is only on the posterior that the 

 deciduous elements are developed. 



In the upper mandible are six pieces viz. : 



(1) A high supranasal saddle extending from side to side (1). 



(2) A longitudinal subnascd lamella on each side (2, 3). 



(3) An oblique taeniform prenasal lamella on each side 

 (4, 5) ; and 



(4) An oblique basal lamella extending from side to side, 

 and distinguished by its punctulate surface (G). 



On the lower mandible there are three pieces viz. : 



(1) An inverted saddle, corresponding to the supranasal 

 one (7) ; and 



(2) A mental lamella on each side at the base (8, 0). 



