KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. N:0 6. 175 



br. 10 mill. One of the extreme varieties is in length 14 mill., hr. nearly 14 mill., 

 height of aperture 10 mill. Another, the opposite extremity is 26 mill. in height and 

 it has probably, when the apex was entire, attained 30 mill. in height, br. of body 

 whorl 14 mill. height of aperture 11 mill. 



This is one of the most abundant Silurian Gastropoda from the neighbourhood 

 of Wisby in the middle limestone (b) and also, though not so common, from the shale. 

 From the sandstone of Bursvik a small specimen has been obtained, which highly re- 

 sembles the Wisby specimens as to their ornamentation, but it is not certain that it 

 belongs here. 



Cycl. delicatulum may. possibly be the shell designated by Angelin in his Mu- 

 seum Palasontol. Suecicum as J^ 49 Littorina? striata, but I have not succeeded to 

 lind a complete series of that collection, containing this species with the others. 



2. Oyclonema? apicatum n. 



Pl. XVIII lig. 36. 



Shell elongate, conical, whorls five, the body whorl more than double the size 

 of the others. They are moderately convex and the suture only slightly impressed. 

 On the body whorl there is a blunt angle, where the umbilical sui^face begins. It is 

 there the semblance as of a slit band, like that in the Pleurotomariaa of the division 

 Multicarinati, but not sufficiently clear enough to decide if the shell really is a Pleu- 

 rotomaria. The surface is finely cancellated and the transverse strise are below the 

 angle bent backwards. The band like sculpture is visible only on the body whorl. 

 The aperture is elongate, ovate, the lips are thin and sharp, and there is no trace at 

 all of any umbilicus. 



The peculiar elongate, succinoid shape sufficiently distinguishes this shell from 

 similar. H. 7 mill., br. 5 mill. 



This shell has been found in two specimens in the red limestone of Sandarfve hill. 



3. Cyclonema cancellatum n. 



PL XVIII fig. 25—27. 



Shell moderately large, turbinate, with seven ventricose whorls, of which the body 

 whorl is nearly twice as large as the spire. The surface is evenly rounded without any 

 prominent keels and it is regularly cross bared by thread fine, longitudinal lines and not 

 quite so prominent, transversal ones, covering the whole surface with minute quadran- 

 gles. Some of the longitudinal lines are at irregular distances rather more prominent. 

 The transverse lines have uniformly the same size and take in several specimens a 

 gentle curve backwards, run else straight and near the umbilicus directed forwards. 

 The aperture is obovate, the lips thin, the outer one in some specimens with a shal- 

 low, gently curved notch which also is clearly indicated by the above mentioned course 

 of the transverse stria9. There is no umbilicus. H. 36 mill., br. 42 mill. 



