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"Viper is a genus of venomous snakes. This family includes many important forms– e. g., the common adder, the asp, extending as far N. as Sweden; the African horned viper and puff adder, the Indian daboia or Russell's viper, and the Indian Echis carinata. The head is relatively broad, somewhat triangular, and generally covered with scales; the eye has a vertical pupil, and there is no pit between it and the nostril; the maxilla bears on each side one functional fang, usually with several reserve fangs beside it; the poison is virulent. The vipers are widely distributed through Europe and Australia; the majority are African. As far as is known they are viviparous."—(Charles Leonard-Stuart, 1911)

Common Vipers

"Viper is a genus of venomous snakes. This family includes many important forms– e. g., the common…

"Viper is a genus of venomous snakes. This family includes many important forms– e. g., the common adder, the asp, extending as far N. as Sweden; the African horned viper and puff adder, the Indian daboia or Russell's viper, and the Indian Echis carinata. The head is relatively broad, somewhat triangular, and generally covered with scales; the eye has a vertical pupil, and there is no pit between it and the nostril; the maxilla bears on each side one functional fang, usually with several reserve fangs beside it; the poison is virulent. The vipers are widely distributed through Europe and Australia; the majority are African. As far as is known they are viviparous."—(Charles Leonard-Stuart, 1911)

Common Viper

"Viper is a genus of venomous snakes. This family includes many important forms– e. g., the common…

This illustration shows the skull of a rattlesnake. ar, articular portion of lower jaw; de, dentary portion; bo, basi-occipatal; mx, maxilla, bearing poison fang; na, nasal; pl, palatine, the front end being represented by a dotted line as though seen through the maxilla; pmx, premaxilla; po, post frontal; pr, prefrontal; pt, pterygoid; qu, quadrate; sq, squamosal; tr, transverse bone.

Rattlesnake Skull

This illustration shows the skull of a rattlesnake. ar, articular portion of lower jaw; de, dentary…

Characteristics of the teeth. Teach tooth consists of a crown or body, projecting above the gum; root or fang, embedded within the alveolus; and the neck, the constricted portion between the grown and the fang. There are 4 classes of teeth: incisors (1), canines (2), premolars or bicuspids (3), and molars (4).

The Teeth

Characteristics of the teeth. Teach tooth consists of a crown or body, projecting above the gum; root…

Structure of the teeth. A tooth consists of 3 structures, the dentine (2), or ivory, the proper dental substance, forming the larger portion; the enamel or adamant (3), a layer covering the crown; and the cement (1), a thin layer on the surface of the fang. A central chamber, the pulp-cavity, occupies the interior, and contains the pulp, a soft, vascular, and sensitive organ, surrounded by a layer of cells, the odonto-blasts, or dentine-forming cells.

Structure of the Teeth

Structure of the teeth. A tooth consists of 3 structures, the dentine (2), or ivory, the proper dental…

"Snake's head. dv., Poison fangs; b., sheath of fang; l., tongue; rl., muscles of tongue." -Thomson, 1916

Snake Head

"Snake's head. dv., Poison fangs; b., sheath of fang; l., tongue; rl., muscles of tongue." -Thomson,…

"Poison apparatus of rattlesnake. A, eye; Gc, poison-duct entering the poison-fang at +; Km, muscles of mastication partly cut through at *; Mc, masseter or constrictor muscle; Mc', continuation of the constrictor muscle to the lower jaw; N, nasal opening; S, fibrous poison-sac; z, tongue; za, opening of the poison-duct; zf, pouch of mucous membrane enclosing the poison-fangs." -Parker, 1900

Rattlesnake Poison Apparatus

"Poison apparatus of rattlesnake. A, eye; Gc, poison-duct entering the poison-fang at +; Km, muscles…

"The Viperine Snakes have a long, perforated, erectile fang on the maxillary bone, which is extremely short and bears no teeth."

Fer-de-Lance

"The Viperine Snakes have a long, perforated, erectile fang on the maxillary bone, which is extremely…

"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are chisel-pointed, and have a head or fang projecting to one side to bite the rail. Spikes are also made split, barbed, grooved, and of other shapes." &mdash;Whitney, 1889 <p>Illustration of a dock spike, used in building docks and piers.

Dock Spike

"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are…

"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are chisel-pointed, and have a head or fang projecting to one side to bite the rail. Spikes are also made split, barbed, grooved, and of other shapes." &mdash;Whitney, 1889 <p>Illustration of cut spike, also called a large cut nail.

Cut Spike

"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are…

"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are chisel-pointed, and have a head or fang projecting to one side to bite the rail. Spikes are also made split, barbed, grooved, and of other shapes." &mdash;Whitney, 1889 <p>Illustration of two railway spikes, used to fasten the rails to sleepers.

Railway Spikes

"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are…

"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are chisel-pointed, and have a head or fang projecting to one side to bite the rail. Spikes are also made split, barbed, grooved, and of other shapes." &mdash;Whitney, 1889 <p>Illustration of a barbed spike.

Barbed Spike

"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are…

"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are chisel-pointed, and have a head or fang projecting to one side to bite the rail. Spikes are also made split, barbed, grooved, and of other shapes." &mdash;Whitney, 1889 <p>Illustration of a spike that is both barbed and forked.

Barbed and Forked Spike

"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are…

"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are chisel-pointed, and have a head or fang projecting to one side to bite the rail. Spikes are also made split, barbed, grooved, and of other shapes." &mdash;Whitney, 1889 <p>Illustration of two forked spikes. When driven into wood, the points spread and hook into the wood.

Forked Spikes

"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are…