94 G. LINDSTKOM, ON THK SILUHIAN (iA.s'I'KOPODA AND PTEROtOlJA OF GOTLAND. 



3. I'l. Liiituu'ssoiii II. 



4. I'l. voluta 11. 



5. PI. claiistriita ii. 



6. IM. gUiiidiforiuis ii. 



7. PI. bifonuis. 



8. PI. latezonata. 



9. PI. Hindei n. 



10. PI. Holini n. 



11. PI. Wisbyensis. 



II. CRISPS. Slit band with distiiiitiutcd, sliar])edged, regular crescents and smooth 

 interstices. Shell ornamented by many keels. 



12. PI. Lloydii Sow. 



13. PI. dolium n. 



14. PI. laqueata n. 



15. PI. tubiilosa n. 



III. FASTIGIAT.ffi. Slit band I'orming a blunt, elevated ridge, crescents flat, ol)lique, 



densely packed; shell finely striated transversally. 



16. PI. robusta n. 



17. PI. la'vissima n. 



18. PI. elliptica His. 



19. PI. bicincta Hall. 



20. PI. qualteriata Sciiloth. 



IV. SIMPLICES. Slit band narrow, plain, with small, regular crescents, shell sur- 



face simply, transversally striated. 



21. PI. valida n. 



22. PI. Othemensis n. 



23. PI. comata n. 



24. PI. asquilatera Waiilenbeug. 



V. INOIS.^. Slit band with large, lamellar crescents which are divided in their 



middle. Shell richly ornamented. 



25. PI. labrosa Hall. 



26. PI. limata nom. nov. 



VI. ALAT^. Slit band forming a large, thinedged keel all around the shell, both the 

 bordering lines of the slit band being widened and having develo])ed into thin 

 lamelke, which have coalesced with their edges enclosing the crescents of growth. 



27. PI. replicata n. 



28. PI. alata Wahlenbekg. 



29. PI. alata, var. subcarinata n. 



30. PI. alata, var. opposita n. 



