LABYRINTHODONTIA (Gr. laburinthos, a labyrinth; odous, tooth).  An extinct order of Amphibia, so called from the complex microscopic structure of the teeth.

LACERTILIA (Lat. lacerta, a lizard).  An order of Reptilia comprising the Lizards and Slow-worms.

LAMELLIBRANCHIATA (Lat. lamella, a plate; Gr. bragchia, gill).  The class of Mollusca comprising the ordinary bivalves, characterised by the possession of lamellar gills.

LEPIDODENDRON (Gr. lepis, a scale; dendron, a tree).  A genus of extinct plants, so named from the scale-like scars upon the stem left by the falling off of the leaves.

LEPIDOPTERA (Gr. lepis, a scale; pteron, a wing).  An order of Insects, comprising Butterflies and Moths, characterised by possessing four wings which are usually covered with minute scales.

LEPIDOSIREN (Gr. lepis, a scale; seiren, a siren—­the generic name of the Mud-eel or Siren lacertina).  A genus of Dipnoous fishes, comprising the “Mud-fishes.”

LEPIDOSTROBUS (Gr. lepis, a scale; strobilos, a fir-cone).  A genus founded on the cones of Lepidodendron.

LEPTAENA (Gr. leptos. slender).  A genus of Brachiopods.

LINGULA (Lat. lingula, a little tongue).  A genus of Brachiopods.

LYCOPODIACEAE (Gr. lupos, a wolf; pous, foot).  The group of Cryptogamic plants generally known as “Club-mosses.”

MACHAERACANTHUS (Gr. machaira, a sabre; acantha, thorn or spine).  An extinct genus of Fishes.

MACHAIRODUS (Gr. machaira, a sabre; odous, tooth).  An extinct genus of Carnivora.

MACROTHERIUM (Gr. makros, long; therion. beast).  An extinct genus of Edentata.

MACRURA (Gr. makros, long; oura, tail).  A tribe of Decapod Crustaceans with long tails (e.g., the Lobster, Shrimp, &c.)

MAMMALIA (Lat. mamma, the breast).  The class of Vertebrate animals which suckle their young.

MANDIBLE (Lat. mandibulum, a jaw).  The upper pair of jaws in Insects; also applied to one of the pairs of jaws in Crustacea and Spiders, to the beak of Cephalopods, the lower jaw of Vertebrates, &c.

MANTLE.  The external integument of most of the Mollusca, which is largely developed, and forms a cloak in which the viscera are protected.  Technically called the “pallium.”

MANUS (Lat. the hand).  The hand of the higher Vertebrates.

MARSIPOBRANCHII (Gr. marsipos, a pouch; bragchia, gill).  The order of Fishes comprising the Hag-fishes and Lampreys, with pouch-like gills.

MARSUPIALIA (Lat. marsupium, a pouch).  An order of Mammals in which the females mostly have an abdominal pouch in which the young are carried.

MASTODON (Gr. mastos, nipple; odous, tooth).  An extinct genus of Elephantine Mammals.