194 



Williamson West American Mitridss. 



WEST COAST MITRAS, NAT. SIZE. 



Figs. 1 and 2. Mitra idse, young. San Pedro, California. 

 Figs. 3 and 4. Mitra idx, adult. San Pedro, California. Epidermis partly removed. 



No. 4 collected by Mrs. E. A. Lawrence. 

 Fig. 5. Mitra idx, adult. San Pedro, California. Epidermis wholly gone, color of shell 



light brown. Collected by Mr. Delos Arnold. 

 Fig. 6. Mitra fultoni E. A. S. Pt. Abreojos, Lower California. Collected by Mr. Henry 



Hemphill. 

 Fig. 7. Mitra orientalis. Peru. 



GENUS MITRA LAM. 



Mitra typical is mitriform, thick, with spire elevated, sharp apex, 

 aperture narrow with a notch in front ; " columella obliquely plicate ; lip 

 rather thick, smooth within." The animal is described as having in gen 

 eral a short foot, siphon somewhat short, proboscis cylindrical, eyes on 

 tapering tentacles, the latter close together on a long and flat head ; color 

 white. The dentition of the group is an important factor. 



