157 



HYDRILLA. 



HYDROCOTTLE. 



189 



33. Abastor. Body cylindrical ; loreal shield none ; anterior frontal 

 4 -si Jed ; posterior ocular 2. 



A. erythrogrammus, the Striped-Wampum. North America. 



34. Raclitia. Head small, conical ; body subcylindrical ; anterior 

 frontal very small, triangular; loreal distinct; posterior ocular. 



R. Indica. India. 



35. Miratia. Head: small, conical ; body compressed ; frontal 

 plates 2 pairs ; loreal none ; posterior ocular 2. 



M. alternant. Java. 



***** Head moderate, depressed ; frontal shields, 2, small, lateral ; 

 rostral shield angular, high, erect, between frontals and nasal. 



36. Ficinia. Head small ; rostral plate large, produced between the 

 frontal, angular and recurved in front. 



P. olivacea. Mexico. 



****** Head small ; frontal shields 2, transverse, band-like ; rostral 

 triangular, subangular. 



37. Prosymna. 



P. meleagrii. Guinea. 



/'. Id ad covered with small scales; tail with one row of shields 

 beneath; abdominal shield broad, rounded, smooth; nostril in a 

 shield, anterior, sublateral ; scales granular, with rows of keeled 

 scale*. Xenodermina, 



38. Xenodermia. 



X. Javanicm, the Ooniouote. Java. 



Dr. Gray says, " The separation of the specimens of this family 

 into species and genera is attended with great difficulty ; the form 

 and number of the shields of the head, lips, temple, and chin are 

 liable to great variation, not only in the different specimens, but often 

 in the two sides of the same individual. The two ventral series of 

 scales are, in the same specimen, sometimes separate, and at other 

 times united into a shield ; and many specimens have a series of 

 email triangular shields on the edge of the lips, between the su- 

 tures of the lip-shield, not found iu other individuals of the same 

 species. 



" The distribution of the colours on the body appears to be one of 

 the most permanent characters of the species ; but this becomes less 

 distinct in the older specimens, and is often lost in the specimens that 

 have been carelessly or long preserved in a museum." 



The existence of this family of Water-Snakes has undoubtedly 

 given rise to the notion that a large Ophidian, which meets the 

 popular view of a Great Sea-Serpent, exists. In all cases however the 

 reports of the existence of such a creature have been traced to tlie 

 capture or sight of some other animal, or to the exaggerated repre- 

 Hfiitatiom of some other natural object. The Hijdridtf amongst the 

 i>i>/'lia are of comparatively small size, seldom equalling the Boidae 

 in this respect, and falling far short of the enormous dimensions 

 popularly attributed to the Great Sea-Serpent. [BoiD-E ; OPHLDIA.] 



HYDKILLA. [HYDROCHABIDACE.E.] 



HYDRO'BATA, Vieillot'a name for the Water-Blackbirds, Cinclui. 

 [MERULID.E.] 



HYDRO'BATES, Temminck's name for the Sea-Ducks. [DtrcKS.] 



HYDROBOHACITE, a Mineral, occurring in small needle crystals, 

 which appear to be flat six-sided prisms. Its colour is white, with 

 spots of red from silicated peroxide of iron. Hardness similar to that 

 of gypsum. It is translucent. The specific gravity is 1 '9. Found in 

 it collection of Caucasian minerals. The following is an analysis by 

 Hess : 



Itoracic Acid 49'22 



Lime . 1374 



Magnesia 10'Tl 



Water . 26'33 



100 



HYDROCANTHERA, a tribe of Insects belonging to the Penta- 

 merous family of the Coleoptera. They are all aquatic in their habits. 

 'I'll'- principal sections are the Ilytitcida: and Gyrinidte. [DYTiseiD.fi; 



.ID*.] 



HYDROCHARIDA'CE/E, ffydrocharadt, a small natural order of 

 Endogenous Plants inhabiting ditches, lakes, and rivers in various 

 parts of the world. They have tripetaloideous flowers, often separate 

 sexes, and an inferior ovary. The latter character cuts them off from 

 Alumacea and Butamacae, to which they bear some resemblance in 

 habit. VaUitneria ipiralii, a plant of this order, is remarkable 

 for its spiral flower-stalk, which enables it to accommodate itself 

 to the depth of the stream in which it floats, so as always to 

 keep its flowers above water when it is necessary. [VALLISNERIA.] 

 It is in the leaves of this plant that a peculiar movement in the 

 interior of the cell called Cyclotii [G'YCLCSisJ was originally observed. 

 The same movement is also seen in the cells of Ifydrocharw Mor.mi 

 Rant* and Anacharii alpinaelrum, and is probably present in the 

 whole of the order. The species are natives of fresh-water in 

 Europe, North America, and the East Indies. One species is found 

 in Kifypt (Damoimium fndicum), and two Vallisncrias in Australia. 

 .nig is known of their uses unless that the fruit of Enhaliu is 

 ', and its fibres capable of being woven. According to Agardh, 

 Ottilia and Soottia are eaten in India as pot-herbs. 



JTydroclaris Montu liana. 



1, a portion of the plant, with flowers, leaves, and stem ; 2, a male flower; 

 3, a female flower ; 4, a section of the ripe fruit ; 5, a seed, with a part of the 

 esta stripped off to show the embryo. 



The Janji of Hindustan, the Vallinneria, alternifolia of Roxburgh 

 Hydrilla of Hamilton, is one of the plants used in India for 

 supplying water mechanically to sugar in the process of refining it, 

 " as clay is used in the West Indies to permit the slow percolation 

 of water." Lindley places this order near Naiadaceos, Pittiacece, and 

 Bromeliaceft. It has 12 genera and 20 species. 



HYDROCHARIS. [HYDBOCHABACEJS.] 



HYDROCH(ERUS. [HYSTBiciD*.] 



HYDROCOTYLE (from B5wp, water, and KOTUAIJ, a cavity), a genus 

 of Plants belonging to the natural order UmbMiferie and to the sub- 

 order Orthope>~mete. The calyx obsolete ; the petals ovate, entire, 

 acute, with a straight apex; the fruit flatly compressed from the 

 sides ; the carpels without vittae ; the five ribs or nerves nearly 

 filiform, the carinal and lateral ones usually obsolete, and the two 

 intermediate ones joined. The species of this genus are generally 

 bog-herbs ; but few of them are under-shrubs. The umbel is single, 

 surrounded by a few-leaved involucrum ; the flowers sessile or pedicil- 

 late, white. 



Upwards of ninety species of plants have been referred to this genus. 

 It is not however improbable that a more attentive study of them will 

 lead to the distinction of other genera amongst them. 



//. vulgarig, Pennywort, has peltate orbiculate double creuate leaves ; 

 umbels capitate, of 5 flowers, often proliferous: fruit emarginate 

 below. This plant is a native of Great Britain, and throughout nearly 

 the whole of Europe, in marshy bogijy places, and on the margins of 

 rivulets on a peat soil. This plant is commonly called Pennywort, 

 on account of its leaves lying flat on the ground and having the size 

 and form of a piece of money. It is also known by the names of 

 Water-Pennywort, Sheep-Killing Pennygrass, White-Rot, Fluke-Wort, 

 and Sheep's-Bane. These latter names it has obtained on account of 

 its being supposed to produce the rot and other diseases in animals 

 that feed on it. This is however an error, as this plant will not 

 produce disease in animals ; but it occurs iu damp moist situations, 

 where animals that feed are likely to be attacked with rot and other 

 diseases. It is in this way that other marsh-plants, as the species of 

 Drotera and Pinyuicula, have been supposed to cause disease in sheep 

 and oxen. 



Of the large number of species of this genus few if any are used in 

 the arts or medicine, and none of them are sufficiently ornamental to 

 lead to their cultivation. 11. Ariatica is said to be used in India as a 

 diuretic, and occasionally as a culinary vegetable. If. umbdlata is 

 recommended by Marti ua as a remedy in hypochondriasis, but on 



