508 THE NATURAL HISTORY RETTEW, 



notice was not only compiled, but printed. Why it should not have 

 been published twelve years ago is a mystery to us. We perceive, 

 however, from the preface, that " A Supplement, prepared by Dr. 

 Baird, containing addenda, corrigenda, and a notice of additional 

 species found since Dr. Johnston's death, with a complete index, 

 have been added, to render the work more complete." 



At the time when Dr. Johnston drew up this catalogue, there were 

 few, besides himself, in this country who made any very special study 

 of the Annelids. Nor although Savigny, Oersted, Grube, Audouin and 

 Milne-Edwards had, to a considerable extent, reduced a chaotic mass 

 of genera and species to something like order, was this to be wondered 

 at ; for at this present moment, although much additional work has 

 been accomplished, the difficulties in the way of investigating these 

 animals are nearly as great as ever. We purpose to consider by-and- 

 bye why this is the case, but in the first instance, will give a brief 

 analysis of the contents of the book before us. At the outset, we take 

 especial objection to the title of this volume. The division of the 

 Annuloida (even supposing that we exclude from this group the 

 Echinodermata) into parasitical and non-parasitical worms is such a 

 clumsy and unnatural one, that it cannot for a moment be justified ; 

 bringing together, as it does, families in no way related to one 

 another, and separating those w^hich have undoubted affinities. 



The first Order alluded to is that of Turbellaria. The enumera- 

 tion of the British species, accompanied as it is by very brief and 

 uncertain diagnoses, will be of little assistance to the collector. In- 

 deed, even with the late researches of M. de Quatrefages, this order 

 is shrouded in almost Egyptian darkness. A large number of the 

 species here given are Dalyellian, and those who have had occasion 

 to try to identify the new species in Sir Charles Dalyell's works 

 well know how hopeless is the task, in spite of the beauty of many 

 of the illustrations. The genus Stylus^ which dates but from 

 February in this year, is formed for the reception of four species 

 described by Dalyell, in all of which the posterior end terminates in 

 a cartilaginous style. 



The second Order receives the name Bdeliomorpha ; but it is not 

 that order as characterized by E. Blanchard, who formed it for the 

 reception of the genus Malacabdella. It contains the genera, Octo- 

 hothrium, Udonella, Capsahy and JV^itzschia,^ which would appear to 



* Dr. Johnston was generally most accurate in his spelling, and yet we find in 

 one page the following varieties of spelling for this word: — Nitchia, Nitzchia, and 

 NitscJiia, none of them being correct. The latter is the spelling in the Index. 

 Nitzsch lived until 1837. 



