Description

Surf clams like to burrow in rocks, and the shell is consequently quite strongly constructed.  The shell surface is smooth, with concentric growth lines, and covered with a thin periostracum. The resilium (part of the hinge ligament inside the edges of the valves) is large and situated in a chondrophore, the spoon-shaped pit on the interior of the bivalve shell that contains the internal ligament. Lateral teeth are usually present, and the cardinal teetah are weekened. The mantle line has a posterior sinus.

  

 

The shell shown opposite, Mactrellona exoleta, is actually rather similar to Mactrellona clisia. However, a sharp angulation on the left (posterior) end, and the absence of a "keel" at the edge where the shell is flattened identifies it as M. exoleta (Keen).

Classification

Class: Bivalvia

Subclass: Heterodonta

Order: Veneroida

Superfamily: Mactracea

Family: Mactridae

 

Major Genera

• Genus: Anatina
• Genus: Lutraria
• Genus: Mactra
• Genus: Mactrellona
• Genus: Raeta
• Genus: Rangia
• Genus: Spisula
• Genus: Tresus

Mactrellona exoleta (Gray, 1837)
Ripe Mactra

LINK --SEE A LIVING
SURF CLAM