102 Proceedings of the British Association. 



to perform flight with ease. Raptorial birds take a horizontal position 

 when suspended in the air, and the compensating power consists in 

 their taking a more or less erect position when at rest. Another 

 class, including the woodpeckers, wagtails, &c, take an oblique posi- 

 tion in the air : with these the compensating power consists in their 

 cleaving and passing through the air at an angle coincident with the 

 position of the body, and performing flight by a series of curves or 

 saltations. Natatorial birds sometimes need very extended flight ; 

 they take a very oblique position in the air; they have the ribs 

 greatly lengthened, the integuments of the abdomen are long and 

 flexible which enables them greatly to enlarge the abdominal portion 

 of their body by inflating it with air ; this causes a decrease in the 

 specific gravity of that part, and raises it to a horizontal position. The 

 compensating power consists in the posterior half of the body be- 

 coming specifically lighter, while the specific gravity of the anterior 

 half remains unaltered. 



This paper was illustrated by the skeletons of several birds. 



Mr. A. Strickland, observing the guillemot upon the table, 

 stated, that although this bird had the power of flying over the sea, 

 it could not over the land. — Mr. H. E. Strickland had, originally, 

 doubted this fact, but, from experiments he had made on the east 

 coast of Yorkshire, he could confirm the statement of Mr, A. Strick- 

 land. He believed this fact had never been noticed by ornitho- 

 logists. — Mr. R. Ball, of Dublin, stated that he had appended a 

 note, to the effect that the guillemot could not fly on land, in a pa- 

 per which had been published about eight days, by the Irish 

 Archaeological Society. 



Mr. H. E. Strickland read the Report of the Committee 

 ' On the Vitality of Seeds.' — Most of the experiments reported on at 

 previous meetings, were still being continued. The Committee had 

 received a large collection of seeds from Sir Wm. Jackson Hooker, 

 which had been collected between the years 1800 and 1843. Of the 

 seeds, nearly one hundred species, gathered in 1800 and 1801, only 

 two species germinated, a Colutea and a Coronilla. The more recent- 

 ly gathered seeds germinated in a greater per-centage. Thus of 

 forty-two species gathered in 1840, thirteen germinated. Of those 

 which failed, were species of Cannabis, Othusa, Paeonia, &c. 



