238 G. C. Broadhead — Devonian of North Missouri, 



times a faint appearance of a second row. The shell also 

 presents a somewhat nodular appearance just below the suture. 

 The suture is well defined. 



The lower side of the last volution is regularly curved, the 

 upper side more often rough-looking from the presence of 

 nodes and the occasional prominence of the lines of growth. 



On the last volution of old shells the nodes almost disappear 

 but the sulcus continues to be well marked. Columellar lip 

 thick, flattened, making an angle of about 80° with the outer 

 surface of the shell. 



Height of an average specimen _ . 2 inches 



Breadth " " " 2 inches 



Some shells are one-half larger. 



This shell in general form resembles Turbo shumardi of De 

 Yerneuill, but the latter is crossed with swollen ridges instead 

 of nodes and they cross the lines of growth instead of follow- 

 ing them. The T. Shumardi also has no sulcus. The sulcus 

 in our shell seems to be a filled slit and, therefore, we have 

 placed it in the genus Pleurotomaria. 



Columbia, Mo., June 11, 1896. 



Figure l. — Average specimen. 



Figure 2. — Under side of last whorl showing umbilical region. 

 Figure 3. — Part of an old shell showing ornamentation on last whorl. 

 Figure 4. — Yertical section. 



Figure 5. — Part of whorl showing nodes with sulcus between. 

 Figure 6. — Part of an old shell crushed. 



Figure 7. — Section across back of whorl showing sulcus and elevation of ridges 

 and nodes. 



All of natural size. 



