GLOSSARY. 315 



of a spiral proboscis, and of four large more or less scaly wings. 



It includes the well-known Butterflies and Moths. 

 Littoral. — Inhabiting the seashore. 

 Loess. — A marly deposit of recent (Post-Tertiary) date, which 



occupies a great part of the vaUey of the Ehine. 



Malacostraca. — The higher division of the Crustacea, including 

 the ordinary Crabs, Lobsters, Shrimps, &c., together with the 

 Woodlice and Saud-hoppers. 



Mammalia. — The higliest class of animals, including the ordinary 

 hairy quadrupeds, the Whales, and Man, and characterised by 

 the production of living young which are nourished after birth 

 by milk from the teats {Mammse, Mammary glands) of the 

 mother. A striking difference in embryonic development has 

 led to the division of this class into two great groups ; in one of 

 these, when the embryo has attained a certain stage, a vascular 

 connection, called the placenta, is formed between the embryo 

 and the mother ; in the other this is wanting, and the young are 

 produced in a very incomplete state. The former, including the 

 greater part of the class, are called Placental mammals; the 

 latter, or Aplacental mammals, include the Marsupials and 

 Monotreraes ( Ornithorhynchus). 



Mammiferous. Having mammas or teats (see Mammalia). 



Mandibles, in Insects. — The first or uppermost pair of jaws, which 

 are generally solid, horny, biting organs. In Birds the term is 

 applied to both jaws with their horny coverings. In Quadrupeds 

 the mandible is properly the lower jaw, 



Marsupials.-^Au order of Mammalia in which the young are bom 

 in a very incomplete state of development, and carried by the 

 mother, while sucking, in a ventral pouch (marsupium), such as 

 the Kangaroos, Opossums, &c. (see Mammalia), 



Maxilla, in Insects. — The second or lower pair of jaws, which are 

 composed of several joints and furnished with peculiar jointed 

 appendages called palpi, or leelers. 



Melanism. — The opposite of albinism ; an \mdue development of 

 colom'ing material in the skin and its appendages, 



Metamorpiiic Rocks. — Sedimentury rocks which have undergone 

 alteration, generally by the action of heat, subsequently to their 

 deposition and consolidntion. 



MoLLUSCA. — One of the great divisions of the Animal Kin-^^dom, 

 including those animals which have a soft body, usually 



