A MIDDLE CAMBEIAIT FAUNA FROM BENNETT ISLAND 



19 



than in the specimen in question, but these characteristics seem to be variable as is seen in 

 the figures given by Brogger (1878, pi. 4, fig. 1, 5 — 6). 



i A fragment of a small cranidium presents a striking resemblance to A. acuminafus 



(Ang.) in its truncate glabella and its very protuberant and tapering preglabeliar field. 



It is unnecessary to emphasize that the above references of the said fragments are 

 doubtful and in need of further confirmation by more complete material. At all events I do 

 not know any species to which they might more safely be referred. 



Whether A. difformis and A. acuminatus are two distinct species or only varieties of 

 one species, is not as yet fully ascertained. At present I will not express any opinion on 

 this matter. The forms are common in the Paradoxides forcMiammeri zone of Scandinavia. 

 In Norway (and Northern Sweden ?) they already appear in the upper part of the zone of 

 P. davidis. 



Undetermined trilobites 



Some fragments of young or immature forms, which are shown in fig. 20 — 30 of 

 pi. Ill, cannot at present be determined. 



Fig. 20. Incomplete thoracic segment with granulated surface. — Among genera cer- 

 tainly or probably represented in the collection under consideration only Solenopletira has 

 a granulated test. However, this genus is characterized by having the exterior part of the 

 pleurae bent strongly downwards, whereas the specimen in question seems to be almost flat. 



Fig. 21. Poorly preserved pygidium of an immature specimen. It recalls Liostracus 

 micropMJialmus (Ang.) to some extent, but has a shorter axis than the latter. 



Fig. 22 — 27. Specimens at nepionic stages of development. Possibly they might belong 

 to some species of Anomocare, with the embryonic stages of which, however, I am not 

 familiar. 



Fig. 28. Pigidium with attached thoracic segments of immature specimen. 



Fig. 29. Part of pygidium with attached thoracic segments of immature specimen. 



Fig. 30. Part of thorax of immature specimen. 



TABLE OF THE MIDDLE CAMBKIAN FAUNA OF BENNETT ISLAND, SHOWING THE STRATIGRAPHICAL 

 OCCURRENCE OF IDENTICAL OR RELATED FORMS IN SCANDINAVIA. 



Bennett Island 



Related species 



.CO 



° s 







'St 



§J 



o . 



Micromitra ("}) &^. . . . 

 LinguleUa (?) sp. . . . 



Acrotreta sp 



Undetermined brachiopod 



M. pusilla (Lines.) 



