Physical Description

Colour
The mantle that extends over the shell exterior is semi-transparent, with the pinky/orange shell giving the animal a light pink colour (Figure 1). This exterior mantle causes Scintilla spp. to have a soft, fleshy exterior in contrast to most bivalves. The organs of Scintilla spp. are visible through the shell due to its thinness and delicate structure. There are small tentacles or papillae covering the exterior mantle which appear whitish against the pink background. 

Figure 1: Scintilla spp.


Shape
The shell of Scintilla spp. is sub-elliptical, whereby the shell is elongate and egg-like in shape with the umbo and widest point slightly closer to one end than the other. They display bilateral symmetry at the cross-section of the hinge and are dorso-ventrally flattened. The mantle is thin over the sides of the shell, and thickens considerably at the edges giving the impression of 'lips'. 


 Figure 2. The shell of Scintilla spp.


Size
Specimens collected on Heron Island (n=46) ranged between 5-20mm in length and 4-13mm in width.