PHYLLOPODA. 109 



BucephalithuSf 8fC. 



A knowledge of the structure of Artemis has enabled me to pro- 

 pose this Genus, PI. 5, f. 1,2,3, to which it shows a considerable 

 approximation. It is composed of the Entomolithus Paradoxus of 

 Linnaius, PI, .5, f. 1, the Entomolithus Bucephalus, f. 2, and Spi- 

 nulosus, f. 3, of Wallenberg. As these, together with the other 

 Eyeless Trilobites which constitute the Genus Paradoxides of Des- 

 marest, are only found in a particular formation in Sweden, it will 

 be advantageous to describe this formation before entering into fur- 

 ther details. 



The Transition formation in Sweden, appears to consist of three 

 kinds of stratified rocks, viz. 1st, Alum-slate, containing beds of 

 swine-stone, this, which is the lowest in position, contains the Eye- 

 less Trilobites, which are not found in any other stratum, and are 

 associated with a very small ammonite.. . 2d, a dark coloured Tran- 

 sition Lime-stone, placed over the former, the most essential of the 

 three strata, containing a variety of fossils, but principally large Or- 

 thoceratites and Entomostracites,. . and 3d, Argillaceous Shistus, 

 very different from the aluminous shistus, never containing swine- 

 stone or other calcareous matter. Its fossils are as it were derived 

 from the calcareous stratum, over which it is placed, but they are 

 so reduced in size and so thin, that they mostly appear as impres- 

 sions (Grapsolithes). This last stratum is found but in a single 

 Province. 



The Alum works Mr. Wallenberg points out as the most produc- 

 tive of these extraordinary' fossils, are as follows, viz. " Those which, 

 are opened on the eastern side of Mount Faredalsberget, and parti- 

 cularly that called Olstrop, in the parish of Dimbo, which have 

 yielded the largest individuals. But it is particularly in a new 

 Alum-work named Damman, opened on the north side of Mount 

 Billigen, where they can be procured at the present time." 



Tlie Bucephalithus Tessini, PI. 5, f. 1, Mr. Wallenberg, from 

 its fragments, says it must have attained to above a foot in length ; 

 front semilunar, furnished with large recurved horns ; (the dotted 

 line in the figure is from that given in Desmarcsts Work on the 

 Trilobites.) A great peculiarity in these Bucephalithi, is the whole of 

 the members being perfectly distinct, and unconnected at their ex- 

 tremities. This species is only found in the Aluminous Shistus of 

 Westrogothland, and at such a depth as the quarries scarcely attain 

 at the present time (1818,) the shist being too hard for thepm-po.~e 

 of procuring akun. 



The Entomostracites Bucephalus of Wallenberg, of which f. 2 is 

 the anterior portion, I should regard as the female of the former, 

 differing in the horns being much smaller, and extending outwards. 

 With the former species, it is found in the inferior aluminous shis- 

 tus, and in the adjacent swine-stone, but as yet, only the Head is 

 known. Tlie impressions obtained at Dimbo indicate an animal 

 of large size, as the Horns are as long as four inches ! 



Bucephalithus Spinulosus, PI. o, f. 3, is the Trilobite fisnired by 

 Linuzeus as provided with Antennae, Vest. Act. Handl. 1759, p. 22, 

 t.l, f. 1. Mr. Wallenberg has never .seen any trace of antennae and 

 Mons. Desmarests endeavours to explain thi*^ supposed error of the 



