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In most fossil nautiluses, the siphuncle runs more or less through the center of each chamber, but in ammonites and belemnites it usually runs along the ventral edge of the shell. In some fossil straight shelled nautiloids, cylindrical calcareous growths ("siphuncular deposits") around the siphuncle can be seen towards the apex of the shell.
In anatomy, a suture is a fairly rigid joint between two or more hard elements of an organism, with or without significant overlap of the elements. [ 1 ] Sutures are found in the skeletons or exoskeletons of a wide range of animals, in both invertebrates and vertebrates .
Standard anatomical terms of location are used to describe unambiguously the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on.
Brachiopods have two valves (shell sections), which cover the dorsal (top) and ventral (bottom) surface of the animal, unlike bivalve molluscs whose shells cover the lateral surfaces (sides). The valves are unequal in size and structure, with each having its own symmetrical form rather than the two being mirror images of each other.
The turtle shell is a shield for the ventral and dorsal parts of turtles (the order Testudines), completely enclosing all the vital organs of the turtle and in some cases even the head. [1] It is constructed of modified bony elements such as the ribs, parts of the pelvis and other bones found in most reptiles.
The ecdysial suture is longitudinally placed on the vertex, separating the epicranial halves of the head to the left and right sides. Depending on the insect, the suture may come in different shapes: like either a Y, U or V. Those diverging lines that make up the ecdysial suture are called the frontal or frontogenal sutures.
The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some gastropods appear shell-less but may have a remnant within the mantle, or in some cases the shell is reduced such that the body cannot be retracted within it .
Human anatomy is the scientific study of the morphology of the adult human. It is subdivided into gross anatomy and microscopic anatomy . Gross anatomy (also called topographical anatomy, regional anatomy, or anthropotomy) is the study of anatomical structures that can be seen by unaided vision.