General Characteristics
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Shell and Associated Structures
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Gas Exchange, Filter Feeding, and Digestion
- Lamellae: folded sheets form by gills; one end attached to the foot and the other end attached to the mantle
- have gills
- Suprabranchial Chamber: where water exits the bivalve through a part of the mantle cavity at the dorsal aspect of the gills
- Food Grooves: where cilia moves trapped food particles to ciliated tracts called food grooves; move food toward towards the mouth
- Labial Palps: cilia covering leaflike labial palps on either side of the mouth sort filtered food particles
- Pseudofeces: rejected food; ciliated tract on the mantle direct this material posteriorly
- Crystalline Style: a consildated mucoid mass; projects into the stomach from a diverticulum, called the style sac; incorporate enzymes for carbohydrates and fat digestion
- Gastric Shield: cilia of the style sac rotate the style against a chitinized gastric shield; this abrasion and acidic conditions in the stomach dislodge the enzymes
Other Maintenance Functions
- open circulatory system
- blood flows from the heart to tissue sinuses, nephridia, gills, and back to the heart
- 2 nephridia below the pericardial cavity (the coelom)
- duct system connects to the coelom at one end and opens at the nephridiopores in the anterior region of the suprabranchial chamber
Nervous System
Reproduction and Development
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Bivalve Diversity
- nearly all aquatic habitats
- may completely or partially bury themselves in sand or mud
- attach to solid substrates
- bore into submerged wood, coral, or limestone