1107 



VIOLACE.tf. 



VIPERIDjE. 



leave* ; lyrate nubpalraato-pinnatitid leaflet . This plant is a native of 

 mout mountainous putum in Wain, the north of England, and 

 Scotland. The other l!ritih species are V. lylvaliea and V. ttaynina. 



In their geographical distribution the ipeciei of violet are materially 

 influenced by climate. " The species from tropical countries," says 

 Professor E. Forbes, " are mostly from localities where the influence 

 of elevation has neutralised or modified the climatical influence. 

 The various sections of the genus have geographic centres, as may be 

 seen in the congregations of the allies of V. hirta in North America, 

 and of those of I . tricolor in alpine Europe. North America may 

 be looked upon as the capital of the whole genus, since we find there 

 representatives of all its subdivisions. In the following table the 

 li-tribmion of 75 species, according to the form of their nectaries, is 

 exhibited: 



VIOLA'CK.K, Violel-Worlt, a natural order of Exogenous Plants. 

 It has the following essential characters : Sepals 5, persistent, with an 

 imbricate aestivation, usually elongated at the base. Petals 5, hypogy- 

 nous, equal or unequal, usually withering, and with an obliquely con- 

 volute activation. Stamens 5, alternate, with the petals occasionally 

 opposite them, inserted on a nypogynous disc, often unequal ; antheis 

 bilocular, bursting inwards, either separate or cohering, and lying 

 close upon the ovary; filaments dilated, elongated beyond the anthers ; 

 two in the irregular flowers, generally furnished with an appendage or 

 gland at their base. Ovary 1 -celled, many-seeded, or rarely 1 -seeded, 

 with 3 parietal placenta; opposite the three outer sepals ; style single, 

 usually declinate, with an oblique hooded stigma. Capsule of 3 valves, 

 bearing the placenta; in their axis. Seeds often with a tumour at their 

 base; embryo straight, erect in the axis of fleshy albumen. (Lindley.) 

 The species are herbs, umlershrubs, or shrubs with alternate rarely 

 opposite leaves, simple, usually involute before expansion, and all fur- 

 nished with stipules. The flowers are erect or drooping, axillary, 

 seated on peduncles, which are 1-flowered, solitary, or numerous, 

 sometimes branched. 



Violaeea are related to Polygalacea, Dorseractce, and Patrijtoraccce. 

 The order is divided into two tribes, Videos and Altodincas. The 

 former chiefly inhabit Europe and America j the latter, with the 

 exception of the genus I'cntalol/a, are natives of South America and 

 Africa. This order embraces 11 genera and 300 opecies. 



4 1 



I'iata ptdata. 



I, >nlire plant; !, corolla sr.d caljri of flower removed, to rhow the anther* 

 and nrctarr ; 3, aUmrn ; 4, section of capsule ; i, section of seed, howitiK the 

 rmbrro. 



All the Violafca possess in a greater or less degree emetic proper- 

 ties, which reside principally in their roots ; the principle on which 

 thin property seems to depend has been separated by Boullay from 

 some Kpeciea of Viola, and hai been called Violina. Viola oitorala 

 is admitted into the Edinburgh and l.iuhlin I'harmacopouas for the 

 purpos* of making a strap of the flowers, which is used on account 



of its scent, and Is administered to children as a laxative : it is also 

 used as a test of acHity and alkalinity, being rendered green by 

 alkalis and red by acids. [CEPUAEU8 ; IOXIDIUM ; VIOLA.] 



VIOLKT. |Vlol.\; VlOLACE*.] 



VIl'KK. ryinUM.] 



VIPRB'8 BUQLOea [ECHIDM.I 



VIPER'S GRASS. [SCOKZO.NKRA.] 



VIPKRIIXiE, a family of Snakes, which are thus characterised by 

 Dr. J. E. Gray : Face without any suborbital pit on the side ; upper 

 jaw toothless, with fangs in front ; rostral shields broad, band-like ; 

 scales keeled (except in Acanthopkit) ; tail short, tapering. 



The following synopsis of the genera is given in the 'British 

 Museum Catalogue : ' 



I. Head depressed, rounded on the sides, covered with acutely- 

 keeled scales. 



a. Nostrils large, subsuperior, anterior, hi the centre of a ring- 

 like shield, edged with a large scale above. Uluthunina. 



1. Ddboin. Eyes convex, pupil round ; head elongate ; scale* 

 regularly keeled ; nasal shield smooth in front It is found in India. 



2. Clullio. Eyes convex, pupil oblong, erect ; head short, brood, 

 scales keeled, ending in a spine ; nasal shield interrupted by a small 

 shield in front. It is found in Africa, 



6. Nostrils small, subanterior, sublateral. Ccrastina. 



3. Cerastet. Suboaudal plates 2-rowed ; nostrils lunate on the 

 hinder part of a small nasal plate ; eye-lid of males horned. 



4. /.Wii. Subcaudal plates 1-rowed; nostrils minute in suture of two 

 small scales; the anterior frontal shields minute, smooth ; pupil round. 



II. Head more or less shielded ; nostrils anterior, lateral. 



a. Head flat-topped, high on the sides, shielded in front ; nostrils 



in tha middle of a shield ; tail-end simple ; subcaudal plates 

 2-rowed. Viperina. 



5. Vipera. Superciliary shield distinct; rest of the head covered 

 with small smooth plates ; nose more or less recurved. 



6. Peliat. Vertebral, occipital, aud superciliary plates distinct ; 

 front of head with small shields ; nose blunt. 



b. Head ovate, rounded on the sides, crown entirely shie 1 



nostrils between two plates ; tail-end simple ; subcaudal 

 plates 2-rowed. ffepedonina. 



7. Stpetlon. Scales keeled ; loreal shields none ; one anterior and 

 three posterior ocular shields ; subcaudal shields 2-rowed. 



c. Head depressed, shielded, prominent over the eyes ; nostrils 



between two shields ; tail ending in a recurved spine ; 

 subcaudal plates 1-rowed. Acanthophina. 



8. A canthophit. Head-shield rather scale-like ; loreal none. 



III. Head dilated, depressed, covered with acutely-keeled scales, 



rounded on the sides. 



a. Nostrils large, subsuperior, anterior, in the centre of a ring- 

 like shield, edged with a large scale above. Clothonina. 

 The family contains 9 genera and 20 species, of which 2 genera and 

 4 species are from Asia, 5 genera and 12 species from Africa, 2 genera 

 and 3 species in Europe, and 1 genus and 1 species from Australia. 



One of the most characteristic features of this group of animals is 

 the possession of glauda which secrete a poison with which they destroy 

 their prey. 



The machinery which enables the venom-snakes to inflict the wounds 

 by which they kill is seen in the accompanying plates. 





Tooth and poison-gland of Trig> nocppha!nt nmtui. 



a n, poiion. gland ; 6, duct; e, fanir: the letter indicates the position of the 

 flit, from which the poison passes Into the wound. 



