1^4} Discoveries of Miiller and others in the 



occasionally drop to a third below the key, but soon resume 

 it again. They always sing upon a bush near the ground, and 

 often in the night as well as by day. 



The last to be mentioned in this communication is, de- 

 servedly, not only at the head of its tribe of warblers, but at 

 that of the whole feathered race; viz. the nightingale (Sylvia 

 jLuscinia). It is unnecessary to describe the widely celebrated 

 song of this delightful vocalist. For richness of tone, whether 

 in his highest or lowest notes, he excels all others. He per- 

 forms passages in both the major and minor keys. In the 

 former he raises an acclaim of joy ; in the latter he expresses 

 a kind of wailing affection. The only drawbacks on his merit 

 as a melodist, are his squeaking intermediate notes, which 

 unite his fine and more audible passages. 



Two other Continental warblers have been lately added to 

 the British lists ; viz. the Sylvia alpuia and the Sylvia 

 suecica, but they are as yet but little known. It is said that 

 ornithologists have in contemplation a new arrangement of 

 this interesting genus ; by which it will be divided into two 

 or three sections. 



Chelsea, August 8. 1829. J. M. 



(To be continued.^ 



Art. V. An Account of the Discoveries of Miiller and others in 

 the Organs of Vision of Insects and the Crustacea. By George 

 Parsons, Esq. 



Sir, 

 In the works on natural history recently published in this 

 country, at least in those examined by me, no notice has been 

 taken of the curious discoveries in the organs of vision of the 

 lower animals, made within the last few years on the Continent, 

 and principally by Professor Miiller of the University of 

 Bonn. Some account of these discoveries may perhaps not be 

 unacceptable to your readers : should such be your opinion, 

 the following is at your service. Professor Miiller's first dis- 

 coveries on the subject were published at Leipzig in 1 826, in 

 a work on the comparative physiology of the sense of vision 

 in insects {Zur vergleichenden Physiologie des Gesichtssitmes) ; 

 a paper from him on the same subject appeared subsequently 

 in the Archiv fiir Anatomie und Physiologie von Meckel for 

 January and June 1829, * and a short article, confirming the 



* A brief analysis of this paper is given in the first number (new series) 

 of the Journal of Science of the Rot/al Institution, 



