PREFACE. 



To a work comprising such an extensive body of science as the 

 Handbook of Zoology of Prof. Van der Hoeven, it is impossible 

 that in a few years or even months much matter for additions and 

 corrections shoukl not be presented. It is clear, moreover, that 

 tlie printing of a book of more than 800 pages, like the first 

 volume of the English Translation, cannot be completed in a few 

 Aveeks. The English translator, therefore, could not avail himself 

 of the contributions of Prof. Leuckaut who, in the beginning of 

 1856, gave a supplement to the first volume of the German edition 

 [NacJitrdge und Berichtigungen zu dem, ersten Bands von J. Van 

 DER Hoeven's Handlmcfi der Zoologie, printed after the translation 

 of the second volume, Leipzig, Leopold Voss, 1856). At the date 

 of that publication the greatest part of the first volume of the 

 English edition had been already long printed. From the same 

 cause also reference to the second edition of Prof. Owen's Lectures 

 on the Compar. Anatomy and Physiology of the Invertebrate Ani- 

 mals, was for the most part impossible. 



The English translator, however, gave in the body of the first 

 volume additions and remarks in great part similar to those which 

 are to be found in Leuckart's comprehensive review of the pro- 

 gress of Zoology during the six or seven years subsequent to the 

 publication of the first volume of the original. In the chapter on 

 the Infusories he made a large use of Prof. Stein's observations. 

 Amongst these the affinity asserted to exist between Vorticelloi and 

 Acinetce would seem to have been disproved by Dr Lachmann 

 (Mueller's Archiv f Anat. v. Physiol. 1856, pp. 340—398), who 

 followed the roving embryos from Acinette until, having fixed 

 themselves, they lost their cilia and developed the peculiar suctorial 



