8o 



JOHAN KIÆR. 



M.-N.Kl. 



It is at all events quite different from the articulation that was disco- 

 vered by Burmeister in certain Trilobites, e g. Pliacops, and which were 

 described subsequently by \'olborth- in the case of Ulaeuiis and by Brøg- 

 ger^ in Asaplius cxpaiisus. I reproduce Brøgger's excellent drawing of 



the articulation of the latter form and 

 the articulation of the existing genus 

 Astaciis. Both exhibit quite the same 

 principle. On the inner side of the 

 posterior edge of the segments of 

 Asaphiis we see an articulation pro- 

 cess that falls into a articulation cavity 

 on the anterior part of the succeeding 

 segment. There is thus an inner 

 articulation that cannot be seen from 

 the outside. 



Occurrence. This large form 

 is not uncommon in the Holmia 

 shales at Tomten ; there are a con- 

 siderable number of specimens in my 

 collection, but there are no complete 

 ones. 



Remarks. As further shown 

 when discussing the new genus Kje- 

 rulfia (page 73) it is probably close- 

 ly related to the form from Skåne 

 described by Moberg as Holmia 

 Lundgreni. It difters clearly, howe- 

 ver, in a number of features from 

 the Norwegian form, nor is it at all 

 near the latter in point of size. Thus 

 the frontal lobe of Lundgreni is even- 

 ly rounded anteriorly and is not 

 pear-shaped like that of lata ; further 

 the genal spines are different in form, 

 and the hypostome much more elong- 



Fig. 15. a-b. Cavity and process of arti- 

 culation in Asaphiis e.xpansus after \V. C. 

 Brøgger, c-d. Apparatus of articulation 

 in the recent Astacns after Lang, with 

 connectiv tissue between the segments and 

 the musculature. 



' Organisation der Trilobiten, Berlin 1843, pag. 29. 



- Über die mit glatten Rumpfglieder versehenen Trilobiten etc. (Mem. d. l'acad. imp. d. 



Sciences de St. Petersb. Ser. 7, Vol. VI, No. 2, 1863, pag. 7.) 

 3 Über die Ausbildung des Hypostoms bei einigen skandin. Asaphiden. (Bh. K. Svensk. 



Vet. Akad. Handl. Bd. II, 1886, pag. 70.) 



