220 Letters, Extracts, and Notes. 



six occasions, and, what is more surprising, in the British 

 Islands and in Heligoland. 



I am, Sirs, yours &c. 

 20 Via Pandolfma, Cecilia Picchi. 



Florence, Italy. 

 November 17th,- 1909. 



Heel-pads on Young Birds. — It lias been pointed out to 

 us that the existence of heel-pads in certain species of birds 

 that nest in hollow trees (see Gunther, Ibis, 189U, p. 411, 

 and Stonham, Ibis, 1909, p. 619) was well known to Nitzsch, 

 who described and figured this curious structure in his 

 ' Pterylographie,' p. 134. Taf. v. Nitzsch says (Engl, 

 transl. p. 94j : — 



"In Micropogon erythropygos (i. e , Trachyphonus mar- 

 garitatus) I found on the heel-joint a peculiar circlet of 

 acute tubercles, such as I have also detected in youug 

 Wrynecks." 



These heel-pads have therefore now been detected in six 

 species of two families, namely : — 



Pic i ii. v.. 

 lynx torquilla. 

 Gecinits viridis. 

 Dendrocopus macei. 

 Brachypternus aurantius. 



Capitonidje. 

 Cyanops asiatica. 

 Trachyphonti8 margaritatus. 



There can be little doubt, we think, that the use of this 

 peculiar structure is to enable the young birds to ascend the 

 smooth interior of the holes in the trees in which they are 

 hatched. But it would be very desirable that the young of 

 other birds that breed in hollow trees should be examined 

 to ascertain whether they carry heel-pads or any similar 

 organs, and w r e hope that some of our many correspondents 

 in various parts of the world will turn their attention to this 

 subject and let us know the result. — Edd. 



The Lake- Xg ami Expedition. — Letters received from 

 Mr. Woosnam, dated October 1st, 1909. announce that the 

 party was still on the banks of Lake Ngami, and was doing 



