D I P 



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D I S 



nsean system, or insects having two 

 wings. The musca, or common fly ; the 

 culex, or gnat ; and the oestrus, or gad-fly, 

 are familiar examples. In Cuvier's ar- 

 rangement diptera forms the twelfth class 

 of insecta, and their distinguishing cha- 

 racters are said to be the possessing six 

 feet, and two membranous extended wings, 

 accompanied generally by two moveable 

 bodies, called halteres, which are placed 

 behind the wings ; the organs of mandu- 

 cation are a sucker composed of squa- 

 tnous, sectaceous pieces, varying in num- 

 ber from two to six, enclosed in an inar- 

 ticulated sheath, most frequently in the 

 form of a proboscis. In these divisions 

 almost every entomologist is disposed to 

 make alterations, and the systems pro- 

 posed are far too numerous to be re- 

 counted. 



DI'PTEROUS, Two -winged insects ; belong- 

 ing to the order Diptera. 



DIPY'RE. A mineral, a variety of scapolite 

 found in the Pyrenees, thus named by 

 Haiiy. It consists of silica 60'0, alumina 

 20'0, lime lO'O, and some water or 

 loss. 



DIRU'PTION. (diruptio, Lat.) A forcible 

 rending asunder ; a breaking, or tearing 

 away. 



DIRU'PTED. (diruptus, Lat.) Rent asun- 

 der ; broken away. 



Disc. > (discus, Lat.) 



DISK. J 1. Inconchology,the middle part 

 of the valves, or that which lies between 

 the umbo and the margin; the convex 

 centre of a valve, or most prominent part 

 of the valve, supposing it to lie with its 

 inside undermost. 



2. In botany, the central florets of a com- 

 pound flower ; the whole surface of a 

 leaf. 



DISCO'BOLI. The name given to a family 

 of fishes, in Cuvier's arrangement, from 

 the disk formed by their ventrals. The 

 fishes of this family form two genera. 



DI'SCOID. ) 1. In the form of a disc. In 



DISCOI'DAL. $ botany, plants, the petals 

 of whose flowers are set so closely and 

 evenly as to make the surface plain and 

 flat like a dish. 



2. In conchology, when the whorls are so 

 horizontal as to form a flattened spire. 



DISCOI'DES. A genus of fossil echinus, 

 one species only of which has been found, 

 namely, discoides subuculus. 



DISCO'RBIS. A genus of microscopic spiral 

 discoidal univalves. 



These have been thought by some au- 

 thors, and the number includes Lamarck, 

 to be found in a fossil state only; but 

 Parkinson states that they are found 

 recent on our coasts. 



DISCORBI'TES. Fossil shells of the genus 

 discorbis. 



Di'scous. Broad ; flat ; wide, but of a 

 rounded form. 



DISCONTINUITY. Disunity of parts ; ab- 

 sence of cohesion. 



DISCONTINUOUS. Separated ; interrupted. 



DISEMBO'GUE. (Bailey and Johnson give 

 the etymology of this word from desem- 

 boucher, Fr. ; but I do not find any such 

 word as desemloucher in the Dictionnaire 

 de L' Academic ; indeed, the word itself 

 is rarely modernly used.) To roll or dis- 

 charge itself into the sea, as a large river 

 does ; to gain a vent ; to flow. 



DISGO'RGE. (d6gorger, Fr.) To vomit 

 forth ; to eject with violence. 



DISGO'RGED. Vomited out ; ejected with 

 violence. 



DISINTEGRATED. Separated into its inte- 

 grant parts by mechanical division. 



DISINTEGRATION. The separation of a 

 body into its integrant parts by mecha- 

 nical division ; the wearing down of rocks. 



DISK. See Disc. 



DI'SLOCATE. (disloquer,J?r. dislogare,It.) 

 To put out of its proper place. 



DISLOCATION. (dislocation, Fr. dislo- 

 ffazione, It.) The state of being dis- 

 placed ; displacement of portions of the 

 earth's crust. According to the theory of 

 M. De Beaumont, the principal dislo- 

 cations of the earth's crust of the same 

 geological age range in lines parallel to 

 one and the same great circle of the 

 sphere ; those of different ages are parallel 

 to different circles. The geological era, 

 consequently, of the elevation of moun- 

 tains, may be ascertained from the direc- 

 tion of their axes of movement. 



DISPE'RMOUS. (from Sic,, and (nrspfia, Gr.) 

 Two- seeded ; an epithet for fruit contain- 

 ing two seeds only ; stellate and umbel- 

 late plants are thus termed. 



DISROO'T. To tear away by the roots ; to 

 tear from its foundation. 



DISROO'TED. Torn up with its roots ; torn 

 from its foundation. 



DISRU'PTED. Rent asunder ; broken for- 

 cibly away. 



DISRUPTION. A forcible rending asunder ; 

 a tearing away. 



DISSE'PIMENT. (dissepimentum, Lat.) In 

 botany, the partition which divides a 

 capsule into cells. In many plants the 

 dissepiments do not reach to the axis or 

 centre, in some plants the dissepiments 

 are not formed, or subsequently disappear, 

 and leave the placenta in the centre of 

 the ovarium, like a column, with the 

 seeds adhering to it. 



DI'STHENE. ) Disthene is the name 



DI'STHEN-SPATH. $ given by Haiiy, and 

 Disthen-spath by Mohs, to the mineral 

 Kyanite or Cyanite, which last, see. 



DI'STICHOUS. (Siffnxof, Gr. distichum, 

 Lat.) Two-ranked ; applied to leaves 



