KONGL SV. VET. AKADEMIENS HANDL. BAND. 19. N:0 6. 135 



on the very edge of the covering lamella. Those below the band form a large curve, 

 directed forwards with its greatest convexity and with its upper end at the slit band bent 

 backwards. The transverse lines are nearly thrice as large as the longitudinal ones 

 and, where they meet, a thick, blunt nodiile is formed. Above the slit band there are 

 two longitudinal keels and one smaller around the umbilicus. Close below the slit band 

 a sharp longitudinal keel is running and the lowest edge of the whorl is widened into a 

 narrow ridge, which covers the much impressed suture. A great peculiarity, which has not 

 been observed in any other species of the Murchisonias, nor in any other gastropodan shell 

 of the Silurian formation, consists in two interiör, longitudinal keels, of which one 

 narrow and thin, follows the inner wall of the outer side of the shell from the lower 

 corner of the outer apertural lip, where it is placed a little below the lowest keel. 

 It continues on the same level through the whole shell, as may be seen in the longi- 

 tudinal section, given in fig. 6. On the nucleus this ridge has of course occasioned 

 an impression as a narrow groove, fig 4. The other keel runs higher up near the top 

 of the whorls on their umbilical side and corresponds with the narrow ridge, which is 

 visible around the umbilicus. These may in some way be regarded as formations ho- 

 mologous with the continuous ridges which interiorly cover the walls of the Nerinsete. 



The aperture is large, obovate, its outer lip is thin, the inner is lamellar, reflexed 

 and at broadest in its superior corner. The umbilicus is narrow, where it opens, and 

 continues downwards as a hollow axis. 



The shell has in many specimens, especially on the interiör side, an intense ochra- 

 ceous vellow colour, but whether this is due to låter mineral a^encies or to its retain- 

 ing anything of the original colouring is uncertain. H. 12 mill., br. 8 mill. Height 

 of aperture 4 mill., br. 4 mill- 



In all, nine specimens have been found of this curious shell in the gray lirae- 

 stone of Linde klint, on its northernmost side, and also a few specimens on Sandarfve 

 kulle in the gray and red limestone. 



Fam. VII. EUOMPHALIDiE De Koninck. 



Shell discoid or turriculate, on the apical side or on the middle of the body lehorl 

 provided with a shallow notch in the outer lip, in continuation of lohich there runs on the 

 surface of the whorls a slender, elevated ridge, on which the transverse strioe are forming 

 a small angle, directed backwards ivithout any resemblance with a true slit band. llie apex 

 of the shell is commonly filled, with solid calcareous matter of an organic deposit or even 

 divided in various compartments through transverse, imperforated diaphragmata. 



In adopting the name given by De Koninck') to this family it is in a much more 

 restricted sense than he intended and such genera as Straparolus, Straparollina, Maclurea 

 and Rhaphistoma are according to the definition given above not to be included. The 

 shells of this family, of which only the genera Euomphalus, se7isu strictiori, and Loxonema 



') Faune du Calcaire Carbonif. de la Belgique, II, iii p. 107. 



