Royal Society. 59 



in the great herbaria, prove the identity of many so-called species. 

 It is only the converse of a mistake often charged, rightly or wrongly, 

 upon the school to which M. Boreau belongs. Thev are stated to 

 describe species from single specimens ; but they may return the com- 

 pliment by announcing that their opponents combine them upon just 

 as little evidence. For in what does a "series" of individual speci- 

 mens — one from the Himalaya, another from Siberia, and a third 

 from Europe, with a few more from other countries, — differ from so 

 many single specimens of species 1 How can the writers know, in 

 these cases, that they are not samples of plants presenting a con- 

 stancy of character each in its own country ? It is as rash to com- 

 bine as it would be to separate them upon such imperfect evidence. 



But we have perhaps occupied too much space with this matter, 

 and run considerably away from the work proposed for consideration. 

 We therefore conclude by recommending all earnest students of 

 European, and especially British botany to obtain the " Flore du 

 Centre de la France." 



PROCEEDINGS OF LEARNED SOCIETIES. 



ROYAL. SOCIETY. 



April 29, 1858. — J. P. Gassiot, Esq., Vice-President, in the Chair. 



"On the Structure and Functions of the Hairs of the Crustacea." 

 By Campbell De Morgan, Esq. 



The object of this communication is to determine, by (he observa- 

 tion of their anatomical relations, the uses of the hairs and similar 

 appendages to the shell of the Crustacea. The author mentions the 

 observations of those who have of late specially investigated this sub- 

 ject. M. Lavalle noticed the connexion at times of the canals of the 

 hairs with canals penetrating the whole thickness of the shell, and 

 the occasional continuity of the matter which filled the hairs with 

 that which exists in the corresponding canal of the shell. M. llollard 

 says that the canals of the shell which correspond to the hairs, are 

 occupied by membranous investments, which embrace the base of the 

 hairs, and seem to receive an extension of the nutrient system. He 

 suggests that amongst other functions, the hairs may possibly be con- 

 nected with that of general sensibility. Dr. Haekel in a recent pub- 

 lication has shown that the canals of the shell and hair are lined b}' a 

 continuation of the outer layer of the soft internal integument, which 

 he calls the chitinogenous layer. He describes minutely the structure 

 of the inner integument, and his account on the whole agrees with 

 that given by Milne-Edwards ; but he does not recognize the presence 

 in the canals, of any of the elements of the inner integument except 

 the external cuticular or chitinogenous layer ; nor the connexion of 

 these canals with the corium which lies beneath it, and which 

 receives abundantly nerves and vessels. 



According to the investigations of the author, it is with this deeper. 



