ONONIS OPETIORHYNCHUS. 



349 



more especially since our summers have been so very 

 unsettled. Saintfoin hay is preferred for fatting deer 

 by the park-keepers, and always commands the 

 highest price in the hay-markets. It is also a useful 

 pasture plant, particularly in dry summers, its deep- 

 running root reaching moisture when other shallow- 

 rooting plants are burnt up. Saintfoin should not be 

 grazed late in the spring, lest the points of the 

 strongest shoots be nibbled off. 



ONONIS (Linnaeus). An extensive genus of 

 annual and perennial trailing herbs and undershrubs, 

 natives of Europe and Southern Africa. The flowers 

 are beautiful, and monadelphous and bearing pods 

 belong to Leguminous, One, the O. spinosa, is a 

 British plant, and known by the name of Rest- 

 harrow. None are in cultivation. 



ONOPORDIUM (Linnaeus). A genus of Eu- 

 ropean herbs, chiefly biennials, belonging to Com- 

 pobita;, and in English lists are called cotton-thistle. 

 O. acanthium is a British plant, which, together with 

 some of the continental species, being stately plants, 

 are admitted into our shrubberies. 



ONOSMA (Linnaeus). A genus of half-hardy 

 herbaceous perennials, bearing pentandrious flowers, 

 and belonging to Boraginea;. Generic character : 

 calyx in five parts ; corolla tubular or bell-shaped ; 

 stamens included or equal with the corolla ; anthers 

 broad at the base ; nuts oval and stony. These are 

 handsome plants, and thrive in rich light soil ; a few 

 should be kept in pots, and placed in a frame during 

 hard frost. 



ONTHOPHAGUS (Latreille). A genus of la- 

 mellicorn beetles of very great extent, belonging to 

 the family Scarabcidce, distinguished by wanting a scu- 

 tellum, as well as the third joint of the labial palpi ; 

 the legs are short and robust, with the tibiae some- 

 what triangular ; the body is short, with the thorax 

 thick, broader than long, orbicular or semicircular, 

 and incised in front. The head, and often the thorax, 

 are armed with horns or spines in the males. The 

 species are of small size, and are found in the excre- 

 ment of various animals. Their colours are often ob- 

 scure. The Scarabeus taurus, Linnaeus, belongs to 

 this genus, and is remarkable for the two strong 

 curved horns on the head of the male, which resemble 

 those of a bull. A single individual of this species 

 has been found in the New Forest in Hants. There 

 are ten British species. 



ONYX. This is one of the forms of the common 

 calcedony, and it is usually marked by an alternation 

 of white, black, and dark brown layers. The ancients 

 attributed wonderful properties to the onyx stone, 

 and imagined that it would cure many diseases if 

 worn on the finger, and on this account it sometimes 

 fetched enormous sums. 



OPAL. There are few minerals that have been more 

 highly valued than this gem. The principal colour of 

 the common opal is white and semi-transparent, with 

 a brilliant lustre. The fire opal on the contrary is of 

 a hyacinth-red colour, and both kinds are found in 

 every part of the world. Wood opal is the only 

 other species of this mineral that is usefully employed. 

 It varies considerably in its colour, and, as its name 

 implies, much resembles the branches of trees. It is 

 principally found in Hungary, and, when cut into 

 plates, is employed by the jeweller and lapidary. 



OPATRUM (Fabricius). A genus of small hetero- 

 merotis beetles, generally found in sand-pits, and 

 belonging to the family Tcnebrionida. The Silp/ia 



sabulosa, Linnaeus, is the type. The body is sub- 

 depressed, the antennae short, with the terminal joints 

 broader and transverse, the anterior tibiae sub-trian- 

 gular. These insects are of black or obscure colours, 

 and feisn death when alarmed. 



OPERCULARIE^E. A small natural order of 

 plants comprising only two genera, viz., Opcrcularia 

 and Cryptospcrmum ; exotic weeds nearly allied to 

 Rubiacecs and Valerianccc. 



OPETIORHYNCHUS. A genus of American 

 birds, with anisodactylic feet, resembling the bee- 

 caters in some of their habits, but differing greatly 

 from them in others. Their characters are : the bill 

 longer than the head, straight, or but slightly curved, 

 and but very slender, depressed at the basal part, but 

 compressed at the tip, which is awl-shaped ; they are 

 not wild and solitary birds, and one rarely meets with 

 them in any other situation than in pairs. They fly 

 about houses, and often enter them, and they are 

 seldom met with in the depth of the close forest. 

 Their wings are short, and their tail is also short, 

 wedge-shaped, and feeble. They are therefore not 

 well adapted for long flights ; but they stand high on 

 the legs, and thus are well adapted for walking:. 

 Their nests are constructed something in the form of 

 ovens, for which reason they have been termed oven- 

 birds by some naturalists. These nests are indis- 

 criminately placed against large branches of trees, 

 the corners of windows, gate-posts, and various other- 

 means of support. The nest is of a hemispherical 

 shape, formed entirely of soft mud by the labour of 

 the birds. The interior of this nest is about six inches 

 in diameter, and divided in] the middle by a partition, 

 through which an opening is left for the passage of 

 the bird from the one chamber to the other. It is 

 understood that the inner chamber is the one in 

 which the incubation is carried on, and it is bedded 

 with soft vegetable matter, in order that it may better 

 answer this purpose. The eggs are four in number, 

 nearly white in the ground, and marked with small 

 reddish dots. Some of the species construct nests ; 

 and it is astonishing that so small a bird should con- 

 struct this kind of nest, and make it so firm in its 

 texture as that it will bear to be agitated by the rude 

 winds at the end of a flexible branch. In order to 

 give this consistency to the large pendent nests, vege- 

 table fibres are intermixed with the other materials, 

 and very firmly worked or matted together. The 

 large nests are usually divided into a number of 

 chambers to which there are various openings. The 

 partitions which divide these chambers from each 

 other, answer another important purpose besides 

 mere convenience to the inmates. They bind the 

 structure together, much in the same way as a house 

 is bound together by the wooden framing of the 

 floors and partition?. We cannot suppose that the 

 birds have the slightest tendency to contrive those 

 partitions for the strengthening of their fabrics ; but 

 still this does not lessen the extraordinary fact, that 

 instinct should be able to accomplish, without any 

 contrivance, far more nice, and even far more scien- 

 tific structures, than man can frame, notwithstanding 

 the use of observation, and reason, and the help of 

 scientific investigation. But. we must not wonder at 

 this ; for there is not a single part in the structure of 

 any animal, or any plant, or in the distribution of any- 

 one portion of mineral nature, which does not, when 

 properly improved, tend to lay the whole fabric of man's 

 boasted science in the dust, and send him to school 



