Carapace, shield, or shell covering, found over all or part of the anterior dorsal portion of an animal. In lobsters, shrimps, crayfish, and crabs, the carapace is the part of the exoskeleton ...

Isopod, common name for crustaceans belonging to the order Isopoda and in the same subclass as lobsters and crayfish. Isopods are characterized by their flattened bodies, lack of a carapace, a...

Port Lavaca, city (1990 pop. 10,886), seat of Calhoun co., S Tex., on Lavaca Bay; inc. 1907. A deepwater port of entry, it is a shipping point for an agricultural (corn, rice, cattle, cotton) ...

Decapod (Gr.,=10 feet), name for invertebrate animals of the crustacean order Decapoda (phylum Arthropoda) including the crabs, the lobsters and crayfish, and the true shrimps, all having five...

Réaumur, René Antoine Ferchault de, 1683–1757, French physicist and naturalist. He invented an alcohol thermometer (1731) and the Réaumur temperature scale, in which the freezing point of wate...

Mud puppy, common name for North American salamanders of the genus Necturus, found in rivers and streams throughout the E United States and SE Canada. The name derives from an erroneous belief...

Raccoon, nocturnal New World mammal of the genus Procyon. The common raccoon of North America, Procyon lotor, also called coon, is found from S Canada to South America, except in parts of the ...

Perch, common name for some members of the family Percidae, symmetrical freshwater fishes of N Europe, Asia, and North America. The perch belongs to the large order Perciformes (spiny-finned f...

Crustacean, primarily aquatic arthropod of the subphylum Crustacea. Most of the 44,000 crustacean species are marine, but there are many freshwater forms. The few groups that inhabit terrestri...

Mucopolysaccharide, class of polysaccharide molecules, also known as glycosaminoglycans, composed of amino-sugars chemically linked into repeating units that give a linear unbranched polymeric...