PREFACE 



The object of the present paper is to give an account of a Middle Cambrian fauna 

 from Bennett Island, north of the New Siberian Islands, which was collected by the late 

 Eduard von Toll by the Russian Polar Expedition of 1900 — 1903, of which he was the 

 leader. With regard to the vicissitudes of these collections which belong to the Academy of 

 Sciences in Leningrad the following facts may be adduced. 



When V. Toll left Bennett Island in October 1902, in a bold attempt to reach 

 New Siberia, a journey that was to end in his death, he was obliged to leave all the collec- 

 tions brought together from the island in a depot. A relief expedition under the leadership 

 of A. Koltschak recovered them in the following summer, but only a select, minor part of 

 them could then be brought home, and reached St. Petersburg in 1904. In this collection 

 there were 22 small samples of a fossiliferous Cambrian shale which were shortly after- 

 wards sent to the late Professor G. Holm of Stockholm for identification and description. 

 In 1 9 1 3 Bennett Island was again visited by a Russian Polar expedition under B. A. Vilkitskij, 

 who brought home to St. Petersburg the rest of v. Toll's collections. 



The collection sent to Holm was subjected to a preliminary study by him; specimens 

 were selected for illustration, and they were reproduced by G. Liljevall. The figures were 

 arranged on four octavo plates, to which, for comparison, was added a fifth one of Swedish 

 species of the genus Anomocare Ang., which the most common forms from Bennett Island 

 were found to be identical with or related to. The plates were printed a couple of years 

 before Holm's death, but owing to other duties he never had time to complete the work 

 and publish his results. 



After Holm's death I was asked to take up and complete his work. When this task 

 was almost finished, Prof. P. W. Wittenburg proposed that I should also undertake the study 

 and description of the greater part of v. Toll's Cambrian collections from Bennett Island 

 brought home by Vilkitskij. Thus in the spring of 1928 I received a collection of 76 samples 

 of a black fossiliferous shale, which proved to originate from the same geological horizon 

 as the collection previously sent to Holm. The same fauna is represented in both collections, 

 but the best preserved specimens are found in the one first received. 



