KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. N:0 6. 189 



Fam. XIII. SCALARID^ Broderip. 

 Gen. CÄLLONEMA Hall. 



1865 Isonema Meek and Worthen p. p. Proceed. Ac. Nat. Se. Philad., 251. 

 1879 Callonema Hall. Palseont. N. York vol. V,ii, 50. 



Shell elongate or short and qlobular, ornamented hy transverse, distantiated lamellar 

 ribs, aperture circular, peristoma continuous. 



This genus was established by Hall to include some Devonian and Silurian spe- 

 cies whicli had to that time been numbered with Isonema, though they rather did not 

 correspond to tlie definition given to that genus by its authors Meek and Worthen. 

 I follow the subsequent authors who hava placed the genus Callonema amongst the 

 Scalaridse. In Sweden it had already appeared in the Lower Silurian times, as there 

 are fine species of it in the Leptsena Limestone of Dalecarlia. 



1. Callonema obesum n. 



Pl. XV fig. 27. 



Shell thick, trochiform, of the same length and breadth, with transverse whorls, 

 broader than high, regularly increasing in size. Whorls five, ornamented with oblique, 

 chordlike, lameliar ribs, directed in a gentle curve, going from the suture backwards. 

 The surface acquires through them a fluted appearance, as these chords are more close 

 together than in the next species, finer and more regular. The aperture and the um- 

 bilical side are destroyed in the only specimen extant. H. 8 mill., br. 8 mill. This 

 specimen belongs to the Museum of the University of Copenhagen, and has been found 

 by Angelin probably in the limestone of Wisby. 



2. Callonema scalariforme n. 



Pl. XV f. 24—26. 



Shell elongate, turriculated and slender, of six moderately ventricose whorls. 

 Surface ornamented by obliquely transverse, thread like lamellaa, and between them 

 with parallel lines of growth. The aperture is ovate and the lips thin. The lamellee 

 project beneath each other as scales, the younger beneath the older and they may pro- 

 perly be regarded as the edges of successiva apertures. H. 15 mill., br. 10 mill. Ano- 

 ther specimen h. 10 mill., br. 5 mill., height of aperture 4 mill. 



Some specimens from the middle limestone of Wisby. 



Gen. HOLOPELLA Mac Coy. 



Syn. 1852. Holopella Mac Coy Brit. Pal. Foss., 303. 



1881. Aclisina De Koninck p. p. Faune Carbonif. II, 3, p. 86. 



Shell elongate, slender, smooth or finely striated, peristome continuous. 



