"22G G. LINDSTRÖM, ON THE SILURIAN GASTROPODA AND PTKROPODA OF GOTLAND. 



Plate X. 



Fig. 1. Pleurotomaria latezonata n., p. 99. 



u 2 — 17. » limata n., p. 114, f. 2 — 5 from Klinteberg, f. 6 — 9 from tlie middle limestone 



strata of Wisbj', f. 10 — 11 variety from the canal near Westöös in Hall, f. 12 speciraen from 

 Wisby seen from the umbilical side with a largely developed slit band, f. 13 details of 

 ornameutation of tlie slit band and tbe surfaee around the umbilicus, f. 14 transverse section 

 of the slit band, imbedded in fine grained rock, f. 15 — 16 slit band of two different specimens, 

 magnified, f. 17, part of a slit band eleven in two parts along its median line to show how 

 the crescentic lamellse continue outward to the thin bordering lines. 



i> 18 — 32. Pleurotomaria alata His., p. 116. All the originals to the figures from Wisby. Fig. 23, 

 near the aperture the crescentic lamellse between the bordering laminje are conspicuous as 

 black lines below the surfaee and they are partially restored by dotted lines where they have 

 been broken away, f. 24 inferior surfaee showing the wavy edge of the slit band, f. 25 

 ornam entation of umbilical surfaee, f. 27 details to elucidate the structure of the slit band, 

 f. 28 ornameutation of apical surfaee from a specimen with a ridge, f. 30 transversally 

 sectioned slit band, magnified, f. 31 extreme edge of a slit band, f. 32 variety from Wisby 

 with downwards anh inwards curved slit band. 



1) 33 — 37. Pleurotomaria alata, var. subcarinata n., p. 118, f. 33 specimen from Lingsarfve in Näs, enclosed 

 in an oolitic nodule, figa 34 — 37 from Djupvik iu Eksta. 



B 38 — 40. Pleurotomaria alata, var. opposita n., p. 119, from Habblingbo, f. 39 apical side of body 

 whorl and part of next whorl, f. 40 ornamentation of umbilical side and slit band. 



