214 G. LINDSTRÖM, ON THK SILURIAN CiASTKOPODA AND 1'TKHOPODA OF GOTLAND. 



Plate IV. 



Fig. 1 — 7. Trernanotus longitudinalis n. p. 86, all specimens from Wisby, f. 5 dorsal keel witli apertures, 

 from a cast, f. 6 magnified details of the same, showing septa like, curved lines, going 

 transversally, marking vvhere apertural lamellte have been situated. 

 » 8 — 12. Tremanotus compressus n. p. 87, from Ostergarn. 

 » 13 — 15. Bellerophon trilobatua Sow., p. 80, from Petesvik, Habblingbo. 



