Tag: phylum annelida

The tube-within-a-tube body plan refers to an organism having a digestive tract with two openings (mouth and anus), which is characteristic of annelids like earthworms.

Trochophore, also called trochosphere, small, translucent, free-swimming larva characteristic of marine annelids and most groups of mollusks. Trochophores are spherical or pear-shaped and are girdled by a ring of cilia (minute hairlike structures), the prototroch, that enables them to swim.  Each segment bears a pair of paddle-like and highly vascularized parapodia, which are used for movement and, in many species, act as the worm's primary respiratory surfaces. Bundles of bristles, called setae, the project from the parapodia.

Pelvic girdle comprises of the usual three bones ilium, ischium and pubis which are fused together into a single innominate or hip bone.

The vestibulocochlear nerve (Cranial Nerve VIII) is responsible for hearing and balance (equilibrium).

The Valve of Thebesius (coronary valve) guards the opening of the coronary sinus into the right atrium and is a characteristic feature of the mammalian heart, such as that of a rabbit.

In rabbit, radius and ulna are separate bones but they are joined at both ends by ligaments.

The corpus callosum is a thick band of nerve fibers that connects the two cerebral hemispheres and is a characteristic feature of the mammalian brain, including the rabbit.

Coprophagy is the practice of eating feces. In rabbits, it is a normal behavior to ingest cecotropes (soft feces) to recover nutrients that were not absorbed during the first pass through the digestive system.

Basal Metabolic Rate (BMR) is inversely related to body size. Smaller animals have a higher surface-area-to-volume ratio and thus a higher metabolic rate per unit of body mass compared to larger animals like elephants or whales.

In rabbits, sweat glands are not distributed over the entire body as they are in humans. They are notably present in the skin of the lips.