EXTERNAL MORPHOLOGY: How many valves does the shell consist of and where are they hinged?
Two; dorsally
EXTERNAL MORPHOLOGY: The oldest portion of the shell
Umbo
EXTERNAL MORPHOLOGY: What do the concentric ridges on the surface of each valve represent?
Lines of growth
EXTERNAL MORPHOLOGY: The hard brownish outer covering
Periostracum
INNER VALVE FEATURES: Tooth-like processes found on the inner surface of each valve, just ventral to the umbo
Cardinal teeth
INNER VALVE FEATURES: Elongate ridge along the dorsal margin of the right valve which interdigitates with two ridges in the left valve. What are these ridges called?
Lateral teeth
INNER VALVE FEATURES: Markings found on the inner surface of the valve where various muscles were attached
Muscle scars
MANTLE AND MANTLE CAVITY: The membrane immediately inside the shell and enclosing the rest of the body. Fuses to create the siphons
Mantle
MANTLE AND MANTLE CAVITY: More ventral and leads into the mantle cavity. Moves water with finely suspended food particles toward the gills and mouth
Incurrent siphon
MANTLE AND MANTLE CAVITY: What lines the incurrent siphon to help move water with finely suspended food particles toward the gills and mouth?
Ciliated epithelium
MANTLE AND MANTLE CAVITY: Where does water leave the mantle cavity?
Excurrent siphon
MANTLE AND MANTLE CAVITY: Stout muscles that hold the valves closed tightly when contracted
Adductor muscles
MANTLE AND MANTLE CAVITY: Two anterior and two posterior of these extend from the body of the mussel to their attachments inside the shell. When contracted they pull the body back inside the shell
Retractor muscles
MANTLE AND MANTLE CAVITY: Sheetlike, prominently-striated structures in the doors-posterior region with a pair on each side of the body
Gills
MANTLE AND MANTLE CAVITY: May be extended forward, when the valves are open, and expanded in the sediment. Tough and muscular. This makes up part of “the body” of the mussel. Helps the animal move
Foot
MANTLE AND MANTLE CAVITY: Softer and less compact. This makes up part of “the body” of the mussel. Contains the stomach, digestive glands, and reproductive organs
Visceral mass
MANTLE AND MANTLE CAVITY: Limp, pointed flaps lying against the body wall anterior to the gills. They occur in pairs on each side of the body and are attached by their broad bases to the visceral mass. They secrete a mucus that entangles suspended food within water. Cilia helps direct this into the mouth
Labial palps
MANTLE AND MANTLE CAVITY: Where can you find the mouth?
Between the bases of the palps anteriorly
CIRCULATORY SYSTEM: What is located after you remove the pericardial wall and is in the region just dorsal to the central part of the gills? Where the heart is located
Pericardial cavity
CIRCULATORY SYSTEM: Hollow muscular sac that envelops the dorsal surface of the rectum as it passes through the pericardial cavity
Ventricle
DIGESTIVE SYSTEM: Appears as a dark, greenish mass surrounding the stomach. Inside foot. Digests and breaks down food
Digestive gland
DIGESTIVE SYSTEM: Can be seen as a coiled tube within the visceral mass surrounded by the reproductive glands. Leads from the stomach to the anterior-dorsal part of the visceral mass
Intestine
EXCRETORY SYSTEM: Occupy dorsal positions in the visceral mass and lie adjacent to the pericardial cavity. Richly supplied with blood from which they extract metabolic waste
Kidneys
REPRODUCTIVE SYSTEM: Ovaries or testes. Yellowish, diffuse mass of tissue surrounding the coils of the intestine. This duct opens into the mantle cavity
Gonads