M AL 



MAM 



prehending the examination both of the 

 animal and of the shell. It differs from 

 Conchology, which is limited to the ar- 

 rangement of the shells, and, in this 

 respect, cannot claim a place amongst 

 the sciences. 



MALACO'PTERY'GII [fxaXaKo^, soft, 

 TTxepuYtoi/, a fin). An order of Osseous 

 Fishes, in which the fins are all soft or 

 jointed. The order is subdivided, ac- 

 cording to the position or absence of the 

 ventral fin, into — 



1. M. ahdominales, in which the ven- 

 tral fins are attached to the abdomen 

 behind the pectorals. These include the 

 greater part of the fresh-water fishes. 



2. M. sub-brachiati, in which the ven- 

 tral fins are brought forward under the 

 pectorals, and the fishes, which are chiefly 

 marine, enjoy a considerable power of 

 ascending and descending in the water. 



3. M. apoda, in which the ventral fins 

 are always wanting, and not unfrequently 

 the pectoral also. 



MALACO'STRACA (/uaXaKor , soft, Sa- 

 rpaKov, a shell). A sub-class of the Crusta- 

 cea, in which the animals have seven tho- 

 racic and seven abdominal segments. The 

 term was given by Aristotle to the modern 

 Crustacea, because their shells were softer 

 than those of the Mollusca, or ordinary 

 shell-fish. The Malacostraca are divided 

 into two groups, according to the attach- 

 ment of the eyes : those with immoveable 

 sessile eyes form the Edriophthalma ; 

 those with moveable pedunculated eyes, 

 the Podophthalma. 



MALACTI'NIA {/jLaXaKo^, soft). The 

 third class of the Radiata, consisting of 

 soft aquatic animals, emitting an acid 

 secretion from their surface, which is 

 capable of irritating and inflaming the 

 human skin, like the stinging of a nettle ; 

 hence the name acalephce, or nettles, has 

 been commonly given to this class. They 

 are divided, according to their modes of 

 locomotion, into the following orders : — 



1. Ciliograda, or those which move by 

 vibratile cilia, as beroe. 



2. Physograda, which float by means 

 of air-sacks, as physalia. 



3. Palliograda, which move by the 

 muscular contractions of a superior dis- 

 coid mantle, as rhizostoma Cuvieri. — 

 Grant. 



MALAY RACE. One of the flve 

 principal divisions of mankind, in which 

 the summit of the head is slightly nar- 

 rowed, the forehead a little arched, the 

 upper jaw somewhat projecting, the face 

 less narrow, and the ft'aiures more pro- 

 208 



minent and better marked than in the 

 negro. This race includes the inhabi- 

 tants of the South Sea Islands. 



MALIC ACID (/ia\oi/, an apple). An 

 acid existing in apples, but generally 

 prepared from the berries of the sorbus 

 aucuparia, or mountain ash. It forms 

 salts with alkaline and magnesian bases, 

 called malates. 



MALLEABI'LITY {malleus, a ham- 

 mer). A property of some metals, by 

 which they are capable of being beaten 

 out into plates, or leaves, by the hammer, 

 as in the case of gold-leaf. This pro- 

 perty depends upon a high degree of 

 tenacity, connected with a certain degree 

 of softness. 



MA'LLEID^. A family of mono- 

 myarian conchifers, in the system of 

 Lamarck, named from the genus malleus, 

 and belonging to the ostracea of Cuvier, 

 the oxygones of Latreille. 



MA'LLEOLUS. This term is Latin 

 for a hammer, and is applied, in the bo- 

 tanical process of layering, to the layer 

 which is separated from the parent plant, 

 from its lower end resembling a hammer- 

 head, of which the new plant represents 

 the handle. 



MALTHA. Sea-wax. A solid, whitish, 

 bituminous substance, not unlike tallow, 

 found in Siberia and Persia. It is, pro- 

 bably, the bitumen candidum of Pliny. 



MALTING. The process of making 

 malt ; it consists in the inducing of an 

 artificial growth or germination of barley, 

 by steeping in water, and then evolving 

 the saccharine principle by the applica- 

 tion of heat. 



MALVACEAE. The Mallow tribe of di- 

 cotyledonous plants. Herbaceous plants, 

 trees, or shrubs, with leaves alternate; 

 flowers polypetalous ; stamens hypogy- 

 nous, monadelphous ; fruit capsular or 

 baccate, containing seed with crumpled 

 cotyledons. 



MAMMA'LIA {mamma, a teat). The 

 fifth class of Vertebrate animals, which 

 are provided with mammary glands for 

 the lactation of their young. To this it 

 may be added, that the visceral cavity is 

 separated into a thorax and an abdomen 

 by a muscular diaphragm, and that all 

 the animals of the class breathe by means 

 of lungs precisely similar to our own. 

 See Zoology. 



MAMMA'LOGY. An unclassical term, 

 denoting the science of mammals, or 

 animals furnished with mammae, includ- 

 ing man, the quadrupeds, the quadru- 

 manous animals, and the whales. The 



