( 507 ) 



described. The (ir^l pictures \vei"e given hv K.ierut.f ^ , after remains 

 of the /'grCn skifer" from Tomten (Tömten?) in Norway. He infoi-med 

 us ah-eady that they came from an ArioneUus-si^ecies. T^ater on they 

 were described by Brögger'), who by diem was in(biced to assume Ihe 

 new species Arionelhis Primaevus. Lljider this head he also ranged die 

 mid-shell that had been pictured by K.terulf in tig. 6. Afterward 

 LiNNAiissoN ^) i)ictured and described remains of this Tribolite. He 

 moreover tells us that the mid-shell pictured l\y K.terut.p as fig. () 

 i-ather seems to belong to a new^ species called Elli})soceplialus Nordeus- 

 ki()ldi, instituted by him in the same essay. His material had been 

 got from the "grlvaclve-skitfern" of Forsemölla near Andi-arum. He 

 dared with certaintv to rant^e under the head Arionellus Primaevus 

 a small mid-shell 5 millimetres hmg, which had been found in a 

 sandstone-like variety of the stone mentioned above. This Avas iiot 

 the case with mid-shells from the ordinary stone, which are about 

 15 millimetres long. He gives as his reasons for not daring to range 

 these latter among Arionellus Primaevus Br(")GGek : first that they are 

 much flatter, secondly that the furrows are much shallower, thirdly 

 that the glabella has no side-furrows, fourthly that the glabella 

 towards the front considerably diminishes in breadth. Why, notwith- 

 standing all this, he at first ranged them under this head, though he 

 had never heard of transition-forms, he explains by saying that 

 Barrande had found exactly the same difference between the old 

 and the young specimens of the Bohemian species Arionellus (letice- 

 phaliis Barr., of which transition-forms are known. 



The very same }>oints of difference occur in the Trilobites-remains 

 of the erratic-block found at Vries. Here, however, the glabella of 

 the older specimen does not diminish in breadth more considerably 

 than that of the younger individuals. 



As I wished to be as certain as possible in my determination, I 

 wrote to Prof. Moberg, director of the Geological Institute at Lund, 

 to ask whether there was ajiy material for comparison at my disposal 

 there. Remains of this species of Trilobites seem to be very rare at 

 Forsemölla, however, so that my request could not be complied with. 

 I received as a present, however, a mid-shell of the Ellipsocephalus 

 Nordenskioldi, which seem to occur more frecpiently there. Prof. 



1) Kjerulf „Sparagmitfjeldel". Universitetsprogram Kristiania. 1872. p. 81. l"'ig. 

 7-9. 



3) Brögger, Om ParadoxidesskilVene veil Krekling. Nyt Magazin for Nalurviden- 

 skab. 1878. Bd. ^24. p. 58. 



•') LiNNARSsoN, Dc undre Pa'"adoxideslagren vid Aiidrarnm. Sveriges geologiska 

 Undersökning 1882. Ser. C. N". 51. p. 21. Taf. IV. fig. 3, 4. 



