50 University of Michigan 



PLATE I. 



All drawings were made with the aid of the camera lucida. The 

 scales in figures i, 2, 3, 4, and 6 represent an actual length of i mm.; 

 that of figure 5, 10 microns (i.oi mm.). 



Figure i. Lcptinaria (Xcosiibuliiia) gloynii. 



Figure 2. L. gloynii. Apical whorls. 



Figure 3. L. gloynii. Last whorl, opened to show arrangement 

 of columnellar and parietal lamellae. 



Figure 4. Microcrainns bonaircnsis curacoana. Outline of 4 indi- 

 viduals of type lot to show extreme variation in shape 

 and size. 



Figure 5. -1/. b. curacoana. Radula ; central and first laterals in 

 place, 21 st and 35th laterals. The curved line below 

 the scale shows the shape of a single transverse row. 



Figure 6. Chondroponia (?) ravcni. Apical whorls of young 

 shell. 



