80 G. LINDSTRÖM, ON TllK SILITRIAN GASTROPODA AND rTKROPODA OF GOTLAND. 



11. Bellerophon gemma n. 



Pl. XIX lig. 12-14. 



Shell globular, last whorl rather rapidly expanding, in section broadly transverse 

 or elliptical, iTiclining to crescent shape. The iirabilicus is narrow and open, Tho 

 ornatnontation, which cannot be plainly seen without a strong lens, consists of a large 

 slit band, covered by the same sort of densely crowded lines which decorate thc sides 

 and join the slit band in an angle of 63°. They are longitudinally streaked with 

 elevated wrinkles, larger towards the opening and attenuated backwards. H. 5 inui., 

 breadth at the aperture 6 mm. Only a single speciracn has hitherto been found in the 

 shales of Wisby. Another specimen in good preservation from the red limestone of 

 Saiidarfve kulle comes near to the preceding, but differs in the .slit band not being 

 elevated, only at the same level with the othcr snrface, and also in the ornamental 

 lines being more arched. 



12. Belleroplion pilula n. 



Pl. VI figs. 29—30. 



Shell globular, aperture, as far as preserved, transverse, crescent shaped, more than 

 four times as broad as high. Urabilicus open. Surface covered by a fine network of 

 miiiute, elevated, longitudinal and transverse lines, which enclose regular, quadratic 

 spaces. The slit band indistinct. Height 3 milliin., breadth 2 millim. 



Found in the oldest shale at Djupvik in Eksta. 



13. Belleroplion trilolbatus Sowerbv p. p. 



Pl. IV Kgs. 1.3—15. 



Beäerophmi trilo/intvs. 1S39. SowEKBY in Sil. Syst., 604, pl. 3 fig. 16. 



1840. D'ORBieNy H. Nat. Ceplialop., 209, pl. 7 lig. 24—27. Pl. 8 ligs. 13 is also 



cited, but in tho copy of tho wovk, to which I have had access theve is no 



plate 8. Pcrhaps it has never heen published. 

 18.50. D'Orb. Prodr. I, 31. 



1854. Morris Cat. Brit. Foss., 288. 



1855. Mac Coy Brit. Pal. Foss., 311. 



1856. Sani>berger Vcrstein. des Rhein. Schichtcnsyst., 177, pl. 22 t'., 1 — 3. 

 1867. Sai.ter Silnria 3d Ed , 534, pl. 34 f. 9. 



1873. Id. Catal. Carabr. Museum, 97, 192. 



Shell involute, with three or four broadly and transversally Hattened whorls, 

 which are elliptical in section, and their height contained nearly three times in 

 their breadth. The dorsal surface is divided in three different longitudinal fields 

 through two deep grooves near the sides. The median field is at least of double the 

 size of the lateral ones. As the specimens exist only in casts, there are no vestiges 

 of the shell itself and it is even doubtful whether it really belongs to this genus as 



