228 G. LINDSTUOM, ON THE SILURIAN GASTUOI-ODA AND I'TEKOPODA OF GOTLAND. 



Plate XI. 



Fig. 1 — 7. rieurotomaria prcBtexta n., p. 119. Fig. 5 tlio slit band cloven, the lower stratum shows tlie 

 oblique, cresceutic lamellie of the slit band. Fig. 7 part of the surface around the slit band 

 and its both parallel ridges. 

 « 8 — 13. Pleiirutomaria loijata u., p. 119. Fig. 12 part of apical surface from the suture to the rim of 

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

 Pleurotomaria frenata n., p. 120. 



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



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

 Pleurotomaria Marklini 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. 

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



one is overlaying the inferior. 

 Pleurotomaria lielicina n., p. 124. 



