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bellatse are plants whose flowers grow in 

 umbels, with five petals, and two naked 

 seeds joined at top and separated below. 

 The parsley, fennel, &c. are examples. 



UMBELLI'FER^E. A large order of plants 

 characterized by their flowers being in 

 umbels. Calyx entire or five-toothed. 

 Petals five, usually inflexed at the point. 

 Stamens five, alternate with the petals. 

 Ovary two-celled. Fruit consisting of 

 two carpels, separable from a common 

 axis. Seed pendulous. Herbaceous 

 plants with fistular stems. 



UMBI'LICATED. (umbilicatus, Lat.) In 

 conchology, a term applied to such shells 

 as have a depression in the centre like a 

 navel. Univalves that have the umbi- 

 licus covered in a greater or less degree 

 by a thin process, are termed sub-um- 

 bilicated. 



UMBILI'CUS. (umbilicus, Lat.) The navel. 

 In conchology, a circular perforation in 

 the base of the lower whorl, or body, of 

 many spiral univalves, and common to 

 most of the Trochi, in some of which it 

 runs from the base to the apex. 



U'MBO. (umbo, Lat.) A boss or protu- 

 berance. In conchology, that point of a 

 bivalve shell situated immediately above 

 the hinge. This word makes umbones in 

 the plural. 



U'MBONATED. Bossed ; knobbed in the 

 centre. 



UNCONFO'RMABLE. In geology, a term 

 applied to a stratum or strata lying in a 

 different plane from the subjacent strata 

 upon which they rest. Strata not lying 

 parallel with those beneath them. Sup- 

 posing certain strata to have been up- 

 heaved, so that their inclination is at an 

 angle with the horizon, or even vertical, 

 such strata may all be, notwithstanding, 

 conformable one with another ; if, how- 

 ever, upon these tilted strata, fresh strata 

 be deposited, the more recent strata lying 

 horizontally upon the subjacent vertical 

 or inclined strata, then the superjacent 

 strata are termed unconformable. 



UNCONFO'RMABLY. Not being in the same 

 plane with those upon which they are 

 deposited. Strata lie unconformably 

 when placed upon others having a differ- 

 ent line of direction or inclination. 



UNCTUO'SITY. Greasiness. A character 

 belonging to certain minerals, which is 

 very useful in assisting to distinguish 

 them. Some minerals, when the finger is 

 passed over their surface, or their powder 

 is rubbed between the finger and thumb, 

 feel as if they were coated with some 

 greasy matter. The sensation is different 

 from that produced by mere smoothness 

 of surface. 



U'NDATED. (undatus, Lat. from unda, a 

 wave.) Waved ; having a waved surface. 



U'NDULATED. (undulatus, Lat. from ten- 

 dula, a little wave.) Waved ; having a 

 waved surface. In botany, applied to 

 leaves when the margins are waved ob- 

 tusely up and down. 



UNFA'THOMABLE. Of a depth that cannot 

 be ascertained ; that cannot be sounded, 

 or the depth of which cannot be dis- 

 covered, by a lead and line. 



U'NGUAL. (from unguis, a nail or claw, 

 Lat.) A name applied to such bones of 

 the feet as have attached to them a nail, 

 claw, or hoof. 



U'NGUICAL. The name given to the claw- 

 bone of certain animals. 



UNGUJ'CULATED. Clawed ; possessing 

 claws. 



U'NGULATE. (from ungula, a hoof, Lat.) 

 Shaped like the hoof of a horse. 



UNICA'PSULAR. (from unus, one, and 

 capsula, a capsule, Lat.) Having one 

 capsule only to each flower. 



UNILO'CULAR. (from unus, one, and locu- 

 lus, a cell or partition.) Having one 

 chamber or cell only. In conchology, 

 applied to shells which are not divided by 

 septa into chambers. In botany, applied 

 to seed vessels not separated into cells. 



U'NIO. (unto, Lat. a pearl.) A genus of 

 freshwater bivalve shells, placed by La- 

 marck in the family Nayades, and by 

 Cuvier in the family Mytilacea. Uniones 

 are equivalve, inequilateral, transverse, 

 internally pearly, externally covered with 

 an epidermis, bivalves ; they are com- 

 monly called fresh-water muscles. Mr. 

 Parkinson states that uniones are not 

 known in a fossil state ; Dr. Mantell, 

 however, mentions five species as being 

 found in the strata of Tilgate Forest, 

 namely, Unio aduncus, U. antiquus, U. 

 porrectus, U. compressus, and U. cordi- 

 formis. Of these he states Unio antiquus 

 to be the most abundant. 



UNIPA'ROUS. (from unus, one, andpario, 

 to produce, or bring forth, Lat.) Pro- 

 ducing one only at a birth. 



U'NIVALVE. (from unus, one, and valva, 

 a shell, Lat.) A shell which is complete 

 in one piece. The Linnsean arrangement 

 of shells consists of three orders, namely, 

 multivalves, bivalves, and univalves. 

 Univalves are far more numerous than 

 either multivalves or bivalves, both in 

 genera and species. Univalves are divided - 

 into sections ; those having a spire, called 

 also turbinated shells, and those without 

 a spire. Some conchologists have named 

 those spiral univalves having an opercu- 

 lum, sub-bivalve shells. 



UNIVA'LVULAR. Having but one shell or 

 valve. 



UNMA'LLEABLE. That cannot be extended 

 by hammering; that cannot be hammered 

 out into plates or laminae. 



