S I ALIS SILKWORM. 



683 



which are but little known, and they appear to have 

 been very much confounded with each other. 



THE GREATER SHREW (S. giganlcits} is one of 

 these. It is about half a foot long, with the tail nearly 

 half the length of the head and body. This species 

 is common in many parts of India, where it lives in 

 holes and other obscure places, reposing during the 

 day, and coming abroad only in the night. It appears 

 to have at one time been very generally distributed, 

 if it is not so still ; for it is one of those of which the 

 mummies have been found in Egypt. As a living 

 inhabitant of the world, however, its history is of very 

 little importance. 



THE RAT-TAILED SHREW (S. myoturui) is a spe- 

 cies which appears to rest on very doubtful authority, 

 and even its native country has not been clearly ascer- 

 tained. It is described as having the muzzle thick, 

 the tail round and quite naked of fur, and the fur on 

 the body entirely white. The authorities are not 

 altogether agreed about it ; for some say that both 

 a are white ; while others say that only the 

 female is white, while the male is brownish grey. 

 The probability is, that the white ones are merely 

 albinoes, and that the absence of hair on the tail is 

 also accidental. 



Besides those which we have enumerated, many 

 other shrews are mentioned by authors, and there are 

 probably many more that have not been noticed ; 

 but the history of the shrews is one of the most in- 

 complete in the whole range of the mammalia. That 

 they are very singular animals, and very generally 

 distributed, is well known ; but their habits are so 

 obscure that half of even the little that is said respect- 

 ing them rests very much on conjectural foundations. 



SIALIS (Latreille). A genus of neuropterous in- 

 sects, forming the type of the family SiaKdte, having 

 the antenna? simple and filiform, the mandibles of 

 moderate size, and the wings laterally deflexed when 

 atrest. The type is the Hemerobius lutarius (Linneeus), 

 a very common sluggish insect found in the early 

 spring months in the neighbourhood of water, and by 

 some persons regarded as the May-fly of the angler. 

 It is of a dull blackish colour, with brown wings. 

 The female deposits an immense number of eggs, 

 which she attaches to different aquatic plants, or other 

 matters near water, in which the larvae reside, where 

 they swim very slowly. When full-grown they leave 

 the water and burrow into the earth at the edge of 

 their former abode, where they undergo their trans- 

 formations, the pupa being inactive. 



The other genera belonging to the same family are 

 CoryiiaKt, having very large mandibles, composed of 

 a North American species, and C/iauliocles, having 

 pectinated antennae. 



SIBBALDIA (Linnaeus). A genus of hardy 

 trailing shrubs and perennial herbs, belonging to the 

 fifth class of Linnaian botany, and to the natural order 

 RmncetB. The S. procnnibens is British, and found 

 on northern mountains. 



SIDA (Linnaeus). An extensive genus of herba- 

 ceous annuals and perennials, shrubs and uuder- 

 shnibs, natives of many tropical countries. The 

 flowers are monadelphous, and the genus belongs to 

 Malcacccc. The genus is separated into four divi- 

 sions, and many sections. They are free ilowerers, 

 and frequently ripen seeds in the stove ; by which 

 they are increased, or by cuttings. 



SIDERITIS (Linnaeus). Shrubs, undcr-shrubs, 

 and herbaceous perennials, mostly natives of Europe, 



belonging to the natural order Labiates. These are 

 the Ironworts of English authors, grow in any com- 

 mon soil, and are propagated by cuttings. 



SIDERODENDRON (Jacquin). The Iron-tree 

 of the West Indies, belonging to Rubiacece. It is 

 valued for its timber, which is remarkably hard and 

 durable. The plant is kept in the stove, and is pro- 

 pagated by cuttings. 



SI EVE RSI A (Wildenow). A genus of herba- 

 ceous plants found in the northern parts of Europe 

 and America. They belong to Rosrtcece, delight in a 

 dry sandy soil, and are increased by division or by 

 seeds. 



SIGARETUS (Lamark ; HELIX HALIOTIDKA, 

 Linnajus). This mollusc is concealed in the mantle 

 of the animal producing it. It somewhat approxi- 

 mates the Natica, greatly resembling a very depressed 

 shell of that genus, from which, however, the extra- 

 ordinary width of the aperture, and its spiral short 

 columeila, render it perfectly distinct. This shell is 

 nearly orbicular, but subauriculated, and very much 

 depressed. The left side short and spiral ; the spire 

 flat ; the aperture oval, entire ; extremely wide, and 

 exposing the whole of the interior ; there are two 

 lateral internal muscular impressions. But a few spe- 

 cies of this genus are known, and their habitat appears 

 unconfined to any particular sea. About three spe- 

 cies are known in a fossil state. 



SILENE (Linnaeus). A very extensive genus of 

 annual and perennial herbs, mostly European. The 

 flowers are decandrous, and the plants belong to 

 Caryophyllece. From the gumminess of some of the 

 flowers flies are entrapped. Hence the vulgar name 

 of catchfly. By far the greater number of the spe- 

 cies are mere weeds, but some of them are highly 

 ornamental. 



SILIQUARIA (Lamarck ; SERPULA ANGUINA, 

 Linnaeus). Linnaeus classed this mollusc with the 

 genus Serpula ; but a more careful examination 

 than he bestowed having been made by subsequent 

 naturalists, points out distinctions sufficiently marked 

 to constitute a separate genus. The shell is tubular, 

 very irregularly twisted ; sometimes in a spiral form 

 at the base ; open at the upper extremity, and hav- 

 ing a subarticulated longitudinal dentated fissure the 

 whole of its length, or sometimes closed at a short 

 distance from the summit. The substance of the 

 shell is thin, the aperture round, and the edges sharp. 

 Their habitat is the Indian ocean, and some species 

 are found in a fossil state. 



SILK COTTON TREE is the JJombax ceiba of 

 Linnaeus. It is so called because the seeds are en- 

 veloped in a downy substance like lk. The sub- 

 stance serves for stuffing mattrasses in India, and has 

 been tried to be worked by both spinners and hat- 

 ters, but the fibre is found not to be of sufficient 

 tenacity for such fabrics. 



SILK- WORM. The ordinary name of the cater- 

 pillar of a lepidopterous insect belonging to the sec- 

 tion Nocturna, and family Sombyddce, and systema- 

 tically known under the name of liombi/x Mori of 

 Linnaeus, or the mulberry-tree moth, which, in the 

 winged state, is of a cream-colour, with several trans- 

 verse bands of a darker colour across the anterior 

 wings, and a crescent-shaped central mark. The 

 caterpillar, when full-grown, is nearty three inches in 

 length, and is too well known to need any particular 

 description. The eggs, when good, are of a pale 

 slate or dark lilac colour ; they may be purchased in 



