Amphibians also use their skin for respiration and some small terrestrial salamanders rely entirely on this and have no lungs.

Members of several families of salamanders have become paedomorphic and either fail to complete their metamorphosis or retain some larval characteristics as adults.

Adipose tissue is another important means of storing energy and this occurs in the abdomen, under the skin and, in some salamanders, in the tail.

In air, where oxygen is more concentrated, some small species can rely solely on cutaneous gas exchange, most famously the plethodontid salamanders, which have neither lungs nor gills.

Many aquatic salamanders and all tadpoles have gills in their larval stage, with some ( such as the axolotl ) retaining gills as aquatic adults.

Eggs of some salamanders and frogs contain unicellular green algae.

Caecilians, some plethodontid salamanders and certain frogs that lay eggs underground have unpigmented eggs.

Cave dwelling amphibians normally hunt by smell and some salamanders seem to have learned to recognize immobile prey even when it has no smell.

Little is known of the territorial behaviour of caecilians but some frogs and salamanders defend home ranges.

Unlike some non-mammalian animals ( such as lizards that shed their tails, salamanders that can regrow many missing body parts, and hydras, flatworms, and starfish that can regrow entire bodies from small fragments ), once removed, human extremities do not grow back, unlike portions of some organs, such as the liver.

Like for salamanders, the regeneration of the liver involves dedifferentiation of some cells to a more embryonal state.

The forebrain is well developed and subdivided in most tetrapods, while the midbrain dominate in many fish and some salamanders.

In some salamanders even these are lacking, and the lung has a smooth wall.

Perplexed by the creature, Home kept changing his mind about its classification, first thinking it was a kind of fish, then thinking it might have some kind of affinity with the duck-billed platypus ( only recently known to science ); finally in 1819 he reasoned it might be a kind of intermediate form between salamanders and lizards, which led him to propose naming it Proteo-Saurus.

Examples include some species of ostracods, small salamanders approximately 2. 5 centimeters ( 1 inch ) in length, and tree frogs.

Polyploidy occurs in some animals, such as goldfish, salmon, and salamanders, but is especially common among ferns and flowering plants ( see Hibiscus rosa-sinensis ), including both wild and cultivated species.

** Tetrodotoxin, a microbial product in Fugu and some salamanders

Unlike some other neotenic salamanders ( Sirens and Necturus ), axolotls can be induced to metamorphose by an injection of iodine ( used in the production of thyroid hormones ) or by shots of thyroxine hormone.

* Pedicellate teeth ( the crown of the teeth is separated from the root by a zone of fibrous tissue ; also found in some Dissorophoidea ; the teeth of some fossil salamanders are not pedicellate )

* Operculum ( small bone in the skull, linked to shoulder girdle by the opercularis muscle ; perhaps involved in hearing and balance ; absent in caecilians and some salamanders, fused to the stapes ( ear bones ) in most anurans )

The larvae of some species ( especially those in the South, and Tiger salamanders ) can reach their adult size before undergoing metamorphosis.

However, cladistic analysis of the mole salamanders found that the existence of Rhyacosiredon makes Ambystoma paraphyletic, since the species are more closely related to some Ambystoma species than those species are to others in Ambystoma.

A caecilian's skin has a large number of transverse folds and in some species contains tiny embedded dermal scales.

Bone penetrating the skin and being exposed to the outside can be both a natural process in some animals, and due to injury:

As a biological phenotype being " black " is often associated with the very dark skin colors of some people who are classified as " black ".

The skin on some pieces bristles with black hair (...) A former smith from Poltava, Kulesh worked together with Centurashvili.

Typically, they have smooth, dark skin, although some specimens have a red wash.

The cell-division cycle is a vital process by which a single-celled fertilized egg develops into a mature organism, as well as the process by which hair, skin, blood cells, and some internal organs are renewed.

There is also some limited evidence that some reactive oxygen species are created by visible light in skin, and that these may have some role in photoaging, in the same manner as ultraviolet A does.

The fate of the Galatian people is a subject of some uncertainty, but they seem ultimately to have been absorbed into the Greek-speaking populations of west-central Anatolia thereby giving a fresh transmission of light skin, blue eyed, and fair haired ethno-types into the Greek population which by then had highly intermarried with darker ethnotypes and lost their earlier appearances.

Gelatin is a mixture of peptides and proteins produced by partial hydrolysis of collagen extracted from the skin, boiled crushed horn, hoof and bones, connective tissues, organs and some intestines of animals such as domesticated cattle, chicken, horses, and pigs.

Therefore, some of the symptoms of hyperthyroidism may be nervousness, irritability, increased perspiration, heart racing, hand tremors, anxiety, difficulty sleeping, thinning of the skin, fine brittle hair, and muscular weakness — especially in the upper arms and thighs.

Hephaestus ’ s ugly appearance and lameness is taken by some to represent arsenicosis, an effect of low levels of arsenic exposure that would result in lameness and skin cancers.

* Litz wire: To reduce skin effect losses, some coils are wound with a special type of radio frequency wire called litz wire.

In North and Central America, and to some extent in West Africa, Australia and other parts of the world, every male acquires at puberty a tutelary spirit ( see Demonology ); in some Native American tribes the youth kills the animal of which he dreams in his initiation fast ; its claw, skin or feathers are put into a little bag and become his " medicine " and must be carefully retained, for a " medicine " once lost can never be replaced.

The vine tends to bud early which gives it some risk to cold frost and its thinner skin increases its susceptibility to Botrytis bunch rot.

Subjects were sweating, trembling, stuttering, biting their lips, groaning, digging their fingernails into their skin, and some were even having nervous laughing fits or seizures.

* Introduction to Oriental facial diagnosis ; shorter and in some ways clearer than the book on body diagnosis but covering only the face, skin, hands, and voice.

For example, after he dissected a black male, Malpighi made some groundbreaking headway into the discovery of the origin of black skin.

Nickel was once a common component of coins, but has largely been replaced by cheaper iron for this purpose, especially since the metal has proven to be a skin allergen for some people.

* Scrob / Scrawb: a scratch on one's skin ( i. e.: " The cat gave me some scrob, b ' y " falling into disuse in lieu of scratch )