PREFACE TO SECOND EDITION. 



THE present edition of ' Forms of Animal Life ' was taken in hand 

 by the late Professor Rolleston in the Long Vacation of 1879. The work 

 was carried on with prolonged interruptions, incident to a life of many 

 and varied engagements, until he left England in December 1880. By 

 that time he had completed the descriptions of Preparations 19 ; three 

 new Plates (Pis. IV, VII, IX) had been engraved under his direction, and he 

 had compiled notes upon them, which have been employed in the descrip- 

 tions printed in this volume. 



Soon after beginning his work, the Professor asked me to undertake 

 a joint authorship of the book. The part then assigned to me was to 

 rewrite the descriptions of a certain number of the Preparations, the 

 general accounts of Urochorda, Arthropoda, parasitic Vermes, Coelenterata 

 and Protozoa^ as well as of several minor classes. He read my account 

 of Protozoa, and settled that it should form a model for the accounts of all 

 other groups. As now printed it has been so far modified as to accord 

 with the recent progress of knowledge. 



When Professor Rolleston went abroad he put me in possession of 

 his plans for the rest of the work, handed his papers to me, and expressed 

 a hope that, if he were disabled from completing the new edition, I might 

 be the person to do it in his stead. It is almost needless for me to add 

 that in fulfilling this sacred trust I have endeavoured to carry out his 

 wishes, which were mainly three : (i) to enlarge the descriptions of the 

 Preparations and accounts of the various classes of animals, and bring 

 them to the standard of contemporary knowledge ; (2) to add to each class 

 or group a brief classification ; and (3) to give as full a bibliography as 

 space would permit. 



The method I have adopted to meet the last requisition is to cite 

 the most important and recent authorities which, when consulted, will in 

 most cases give the names of all other accounts worth reading, so as to form 



