228 Miscellaneous. 



the sense of sight in the Annehda, the organ of which should be more 

 easily discovered than that of the other senses, for it is always cha- 

 racterized, even in its most rudimentary state of organization, by the 

 crystalline lens (taken in its most general sense), and by a retina. 



Among the Annelida, Torrea vitrea presents very perfect eyes ; their 

 size is somewhat considerable (0*00 1 millim.) ; they have a crystalline 

 lens, a choroid coat, a vitreous humour, a transparent cornea, &c. ; 

 some others also have a visual apparatus as perfect'or very nearly so. 



In the HermellcB, the SabellcBy and the Terebellce, the question is 

 more difficult of solution, for the eyes are very small and sunk be- 

 neath the integuments ; hence they are not easily detected ; they 

 must undoubtedly be compared with the stemmata of insects. 



Some Annelida have other eyes besides those on the head. M. Qua- 

 trefages believes that he has discovered them upon the branchiae of 

 the SabellcB, and he has no doubt that the red points which we find 

 upon the sides of each ring in several Annelida of the genus Nais 

 are true eyes ; there is however nothing surprising in this, when we 

 recollect the very great independence existing between the various 

 rings of which the body of these animals consists. Again, some ace- 

 phalous moUusca, as Pecten, also present, upon the borders of their 

 mantle, eyes, the nerves of which are not derived from the cerebral 

 ganglion. — Comptes Rendus, Dec. 31, 1849. 



NEW CLASSIFICATION OF TRILOBITES. 



To the Editors of the Annals of Natural History. 



Edinburgh, August 9th, 1850. 



Gentlemen, — I beg you to insert in your first number of the 

 * Annals of Natural History ' the inclosed new classification of Tri- 

 lobites prepared by my friend M. Barrande of Prague in Bohemia, 

 which I recommend to the consideration of naturalists for its simpli- 

 city and clearness. It forms part of the very important work in three 

 volumes, imperial quarto, which that very meritorious person is about 

 to publish, and the first volume of which will be ready in the autumn. 



At the Meeting of the British Association for the Advancement of 

 Science recently held at this place, I pointed out to the Geological 

 Section the beauty of the plates of Trilobites already completed, and 

 indicating the very high value of the work geologically and zoolo- 

 gically, I endeavoured to show that it would throw a more condensed 

 and clear light upon the distribution of all classes of animal life in 

 the older palaeozoic world, than any publication which had yet ap- 

 peared. 



M. Barrande' s 45 genera of Trilobites, as named herein, are divided 

 by him into 250 species. His plates of chambered shells, mollusks, 

 &c. are equally beautiful, and I earnestly solicit naturalists as well as 

 geologists to subscribe to a work, which published in the French lan- 

 guage, has been carried on by the author at a very great cost of time 

 and labour, and in which he has shown the utmost abihty. The high 



