228 U. LINDSTKÖM, ON TIIE SILUKIAN GA8TU(n'Ul)A AN]) PTlOliorulM OF UOTLANJJ. 



Plate XI. 



Fig. 1 — 7. PUurotomaria prcetexta n., p. 119. Fig. 5 the slit band cloven, the lower siratum shows the 

 oblique, cresceiitic lumella; of the slit band. Fig. 7 part of the surface around the slit band 

 and its botli parallel ridges. 

 » 8 — 13. Pleurotomaria togata n., p. 119. Fig 12 part of apical surface from the suture to the rim of 

 the slit band, f. 13 longitudinal section along the wliorls. 

 Pleurotomaria frenata n., p. 120. 



» undulans n., p. 120. Fig. 21 with details of the strueture of the slit band. 



Fig. 22 slit band sectioiied along the outer rim, f. 23 slit band sectioned transversally. 

 Pleurotomaria, Marhlini n., p. 121. 



» cirrhosa n., p. 121 longitudinal section, f. 29 part of apical surface with the 



thin, wavy slit band solded to the body whorl, f. 28 section of the same. 

 30 — 33. Pleurotomaria exquisita n., p. 125, f. 33 section of two whorls showing how the superior 



one is overlaying the inferior. 

 34 — 37. Pleurotomaria lielicina n., p. 124. 



14. 

 15- 



-23. 



24- 



27- 



-26. 

 -29. 



