Amphibians – animals with backbones that require two states of nature to complete their life cycle ("amphi" = both sides, "bios"=life); have soft skin easily penetrated by water, lay eggs in water to keep the developing young moist. Adults may reside on dry land.

Brille – also called the ocular scale, spectacle, or eye cap, the clear membrane that covers the eye in snakes. Unlike an eyelid, the brille is fixed and does not open or close. Turns blue or cloudy when the snake is ready to shed its skin. From the German, meaning "glasses".

Caecilian – worm-like member of the amphibians, they have no legs and burrow underground. Primarily live in tropical soils; there are no caecilians in North America.

Canthus rostralis – In reptiles and amphibians, the line, sometimes a ridge, connecting the tip of the snout with the top of the eye orbit.

Carapace – the top or back shell of a turtle or tortoise. Also present as the exoskeleton (shell) of crabs and other crustaceans, and in spiders

Clutch – group of eggs produced at a single time by birds or reptiles, particularly those laid in a nest.

Crypsis– the ability of an animal to avoid detection. When coloration is used, the form of crypsis is called camouflage.

Deciduous – trees and other plants that lose their leaves in the autumn.

Dorsal / Dorsum – upper side or back of an organism. Contrast with "ventral".

Herpetology – the study of amphibians and reptiles; from the Greek "herpeton" meaning "crawling animal" and "ologia" meaning "the study of". The animals in this group are often referred to by the abbreviated "herps".

Ectothermy- the ability of organism to regulate its body temperature by absorbing or exchanging heat from the environment; via conduction (by laying on warm rocks and absorbing the heat through direct contact, for example) or by radiant heat (by warming themselves in the sun). From the Greek ecto, meaning "outside", therme, meaning "heat". Often previously referred to as "cold-blooded". Contrast with Endothermy.

Endotherapy – the ability of an organism to maintain a steady body temperature, regardless of surrounding environmental conditions. This involves regulating the body's metabolic rate, for example by sweating to cool the body or shivering to warm the body. Previously referred to as "warm-blooded".

Metamorphosis – the process of transformation

Oviduct – a tube (or duct) in female vertebrates through which passes the ovum (or egg) from the ovary (where it is generated) to either the uterus (in mammals) or out of the female's body (reptiles and amphibians, birds)

Oviparous – egg-laying animals

Ovoviviparous – an animal for which the female retains the eggs in her body until just be for hatching OR the eggs hatch in her body.

Parotoid Gland(s) – In True Frogs (Bufonidae), paired skin glands located on the back of the head, behind the eyes, which secrete a toxic alkaloid substance that acts as a deterrent to predators. May be used as a diagnostic feature, since glands may look different in different species.

Parthenogenesis – the process by which female animals reproduce without the participation of males. The young are all female and are genetic duplicates of the mother. Found in some amphibians (salamanders) and reptiles (lizards).

Physiographic Regions – landform subdivisions that are delineated by similar terrain and geologic structure and history. In Maryland, we have from 3 – 8 (depending on how detailed the delineations). Most recognize the Coastal Plain (Upper and Lower), the Piedmont, and the Mountains (which may include the Blue Ridge, Ridge & Valley, and Allegheny, or Appalachian Plateau). Click here for May of Maryland's Physiographic Regions.

Pineal body – also called the pineal gland and the third eye. This tiny organ resides deep in the brain of vertebrates (herps, birds, mammals, some fish); its cells are photosensitive – activated by light. This gland is believed to regulate circadian rhythms, the cycle of activity and rest.

Plastron – the lower part or belly of the shell of a turtle

Rachis – a center shaft from which radiate other structures. In amphibians, applied to gill structure; in plants, applied to leaf structure; in birds, applied to feathers.

Reptiles - animals with backbones that have dry scaley skin which is impervious to water; their eggs have a shell that holds moisture for the developing young. From the Latin "repere" = to creep.

Scute – the enlarged, platelike scale on a reptile; usually refers to the scales on the shell of a turtle

Spermatophore – a packet or capsule of sperm created and presented by the male to the female (amphibians). She may choose to pick up the packet or not, depending on his courtship display. Internal fertilization occurs if she places in her ovipore near the unfertilized eggs. External fertilization occurs if she deposits her unfertilized eggs outside of her body and places the spermatophore on them.

Tuatara – spiny-backed member of the reptiles, they resemble lizards but have significant differences in anatomy and behavior. Tuatara are found only in New Zealand.

Ventral / Venter – the lower or belly side of an organism. Contrast with "dorsal".

Vernal Pools – a confined depression, or basin, with no above ground outlet or stream, that holds water for at least two months out of the year. Generally does not support fish; limited plant life is found only on the edges of the pool.

Tympanum or Tympanic membrane – in frogs and toads, the external eardrum; found behind the eye. In some species, can be used to determine the sex of the individual: in males it is larger than the eye; in females, it is the same size as the eye.

Viviparous – an animal that gives birth to live young. Contrast with Oviparous and Ovoviviparous

Geologic Periods ​​