Class ArachnidaAnatomy
All adults have eight legs Have two futher appendages First pair: the chelicera, serve in feeding and defense Second pair: the pedipalps have been adapted for feeding, locomothion, and/or reproductive function The larvae of mites and Ricinulei have only six legs: the fourth pair appears when they moult into nymphs. Have no antennae or wings bodies organized into two tagmata called prosoma, or cephalothorax, and the opisthosoma, or abdomen. Have an exoskeleton, and they also have an internal structure of cartilage-like tissue called the endosternite is evenly alcified in some opiliones Respiratory System breathe by using their tracheoe, as well as by pluma-branchioe Digestive System, Their disgestive system works by a simple alimentary tube or canal running from the mouth to the anus. -This tube is various in its form, as well as in the intestines issuing from it. |
Nervous System
The central nevous system is in the cephalothorax, which includes the brain. the brain is connected to a large group of nerve cells called ganglion. Skeletal System All arachnids have eight legs, although the front pair legs in some species are converted to a sensory function. Have an exoskeleton to protect their hard shell which hides their soft body. Muscular System Consist of flexor and extensor muscles, situated within the hollows jof the limbs. At their points of union, boss-like marks of impressed spots of various forms and sizes, often presenting by their position distinctive peculiarities of form. Circulatory System The vital fluid is circulated by means of an elongated muscular vessel or heart, varying in form, and, instead of being placed This vessel is often divided into chambers or compartment by valves, having also valvular orifices on its upper side for the flowing in of the fluid nd giving off vessels for its distribution to the rest of the body. Reproduction the male does not transfer spermatozoa directly to the female but rather initiates courtship rituals in which the female is induced to accept the gelatinous sperm capsule (spermatophore). the sperm are transferred to a sac (spermatheca) within the female reproductive system. The eggs are then fertilized as they are laid. |