und Wissenschaftliche Medicin, fyc. 197 



are floated down by the stream. We think it very probable, that, although there 

 may not be any striking difference in their internal organization, that in some 

 points their structure may be modified to suit the peculiar economy, and adapt 

 them to the necessities of their existence. The C- Rhombifer, in its internal 

 structure, bears some affinity to the Ophidi.ins. In general the circulation is lan- 

 guid, and the volume of blood small in proportion to their dimensions. An illus- 

 trative plate of the heart of C lucius is given. 



The second article is from Dr C- T. Von Siebold of Dantzic, on the Sper- 

 mal Ducts of Crustacea, Insects, Gasteropodes, &c. with two explanatory plates. 



Dr Weber of Bonn contributes some very interesting observations on the hip- 

 joint and the theory of motion of the human step. 



Some notices on the anatomy of the windpipe of Anas leucocephalus and 

 Ibis falcinellus, founded on observations made upon a set of preparations in spirit 

 of wine brought from Sardinia by Mr Kiister, with other remarks on compara- 

 tive anatomy, are given by Professor Wagner of Erlangen. 



The windpipe of a male of Anas leucocephalus. was found to have a widen- 

 ing at the top, somewhat like that in Anas clangula, an inch and a-half long, 

 below which the pipe is very narrow. 



In Ibis falcinellus (the common Ibis,) the lower rings of the windpipe are 

 very small, thin and rather round. They run close together, but are not joined. 

 From the whole circumference of the last rings a strong membrane springs, which 

 binds the two bronchials to the windpipe. 



