Mr. W. Thompson on the Birds of Ireland. 171 



fig. 2.) the tube has been stretched, the fibre breaks up into 

 rings ; and at that part nearest the testa where the pressure is 

 considerable, the fibres at first are simply approximated; nearer 

 still to the testa we have union of the fibres, and the reticu- 

 lated duct produced. 

 August 9, 1842. 



DESCRIPTION OF THE PLATE. 



Plate V. 



Fig. 1. Transverse section of a bundle of dotted tubes from Pteris; a, the 



circular or elliptical orifices. 

 Fig. 2. Dotted tube from the same ; a, conical termination. 

 Fig. 3. The same ; o, overlapping extremities. 



Fig. 4. The same, showing how the extended tube uncoils without break- 

 ing ; b, the black line spoken of above. 

 Fig. 5. and 9. Show how the thicker portion when torn presents a ragged 

 edge : this preparation was dried, and the thinner membrane de- 

 ficient. 

 Fig. 6. Early dotted tubes from Aspidium Filix mas. 



Fig. 7. Transverse section of bundle of tubes from Pteris : when the internal 

 surface of the tube is brought into focus the transverse bars may 

 be seen. 

 Fig. 8. and 9. Fibres withdrawn from the membrane in Aspidium Filix 



XXVI. — The Birds of Ireland. By Wm. Thompson, Esq., 

 Vice-Pres. Nat. Hist. Society of Belfast. 



[Continued from p. 59.] 



No. 13. Hirundinidce {continued). 



Common Swift, Cypselus murarius, Temm. Although this 

 bird is common in favourite localities, the species must be set 

 down with reference to Ireland generally as but partially 

 distributed. Along the western range of the island it is ra- 

 ther scarce, and in some extensive districts is never to be met 

 with. 



The swift is more regular as to the time of its appearance around 

 Belfast than any of the genus Hirundo. It may generally be seen 

 during the first week of May, and frequently on the 2nd day of that 

 month. 



In his ' Illustrations of British Ornithology,' Mr. Selby observes, 

 " It has been remarked that these birds delight in sultry weather, 

 with approaching thunder-storms, at such times flying in small par- 

 ties, with peculiar violence ; and as they pass near steeples, towers, 

 or corners of buildings, uttering loud screams, which White, in his 

 ' Natural History of Selborne,' supposes to be a sort of serenade to 

 their respective families. This is fanciful and pretty ; but I should 

 rather be inclined to reason the opposite way, and to consider this 

 action and cry as the consequences of irritability, excited by the 



