Biology 201

Molluscan Anatomy and Diversity

Clam Photographs

Here are some of the digital images of the clam that I have. I am providing these here for you to make the exam go more smoothly. Study these images, but remember that there is no substitute for the real thing. I am not suggesting that all of these shots will be on the exam, nor am I suggesting that these are the only shots I have. Click on the thumbnail to see a larger image.
 

   

        

    

      transverse section of body, including foot

A Key to our Four Common Clams of the Unionidae

1. Pseudocardinal teeth present.......................................................................................................................2
    Pseudocardinal teeth absent........................................................................................................................3

2. Periostracum considerably worn, well beyond umbo; no radial lines on the shell
    .......................................................................................................................Elliptio complanata (Eastern Elliptio)
    Wear on periostracum usually restricted to the umbo or its immediate vicinity; dark radial lines on periostracum
    .......................................................................................................................Lampsilis radiata (Eastern Lampmussel)

3. Nacreous layer thickened at antero-ventral margin; anterior muscle scar distinct
    .......................................................................................................................Anodonta implicata (Alewife Floater)
    Nacreous layer more or less of uniform thickness; anterior muscle scar indistinct or absent entirely
    .......................................................................................................................Pyganodon cataracta (Eastern Floater)
 
 



 

R.F. Lauff
Department of Biology
St. Francis Xavier University
Antigonish, NS Canada B2G 2W5