24 M. Faber on the Breeding Spots of Birds. 



The Uria grylle^ Lestris catarractes, pomarina. and parast- 

 tictty have two eggs and two breeding spots. The Uria Brun- 

 nichii and troilc, Puffimis arcticus, and Procellaria glacialiSy 

 have one eg^ and one spot. The Uria aUe, Alca torda, and 

 Mormonjratercula, have but one egg and two breeding spots. 



The Phalaropus cinereus, and Plaiyrhinchus, lay four eggs, 

 and have but two breeding spots. The Sterna arctica, Lams 

 glaucus, marinuSy and tridactylus, have sometimes three, some- 

 times two eggs, but constantly only one breeding spot. 



These spots are not entirely meant to supply the place of a 

 nest ; they are, therefore, not invariably in an inverse ratio to 

 the building impulse. Certainly, the species which want these 

 spots, as the Sula and Carbo, build a nest ; most of those, also, 

 which are provided with them build no nest, as the Phalaropus, 

 Uria, Alca, Morindu, Puffinus, Sterna, Lestris, Procellaria; 

 but the genus Larus have breeding spots and build nests. 



Their presence is therefore merely a proof of the development 

 of the pairing impulse, but is not to be considered as synony- 

 mous with the laying of eggs or hatching. Birds pluck out these 

 feathers before even they have joined their mates, and without 

 being certain of breeding that year. Therefore I have found 

 them in May, in individuals of the Lestris catarractes, and Pro- 

 cellaria glacialls, which were so far out at sea, and removed 

 from the breeding places of the species, that I had good cause 

 for reckoning these barren birds, which pass the summer with- 

 out breeding. They also exist in the single individuals of the 

 Lestris parasitica, which flock about together. 



After .4iatching is over, these bare spots are very quickly 

 again covered with feathers. All traces of them have disap- 

 peared in August and September, when the young of some 

 species are not yet fledged. 



Analysis of the Stony Pericarp of the Lithospermum officinale. 

 By Captain Charles Le Hunte. (Communicated by the 

 Author.) 



This may be considered one of the most remarkable substances 

 in the vegetable kingdom, its properties, mechanical and chemi- 

 cal, are those of a mineral, rather than that of a vegetable. The 



