-{popular 93irtionari) of &mmatrtt f>nturr. 



of them attach stony particles to their skin, 

 by a glutinous exudation, so as to cover it 

 with a hard crust, resembling that formed by 

 some Annelida. 



SIREN. A genus of remarkable Batra- 

 chian reptiles, peculiar to the Southern 

 provinces of the United States. They have 

 an elongated form, nearly like that of eels, 

 three branchial tufts on each side ; only one 

 pair of feet ; a flattened head, and obtuse 

 muzzle ; eye very small ; the ear concealed; 

 lower jaw armed with a horny sheath and 

 several rows of small teeth ; the upper jaw 

 toothless ; but numerous small, retrovertcd 

 teeth occur on the palatal region. The 

 anomalous organization of this reptile, and 

 its apparent relationship with different fa- 

 milies, rendered it for a long time doubtful 

 to which it belonged. At length Cuvier 

 satisfactorily established, that the Siren was 

 a reptile siti generis, which never could have 

 hind feet, and whose bony framework dif- 

 fered especially from that of the Sala- 

 manders ; that there was no probability that 

 it ever changed its form or lost its branchiae; 

 and that the Siren is consequently a true 

 amphibian, which respires at will throughout 

 its life, either in the water by means of 

 branchiaj, or in the air by means of lungs. 

 The same naturalist adds, that it is to the 

 Salamanders that the Sirens approach most 

 nearly by the structure of the head, al- 

 though neither the general form nor the 

 proportions of the parts have so near a 

 similarity. The Axolotl belongs to a closely 

 allied genus. [See AXOLOTL.] 



SIREX : SIRICIDJE. A genus and fa- 

 mily of Hymeuopterous insects, of which the 

 Sirex gigas may be taken as a tyi>e. They 

 have the antennae jointed, and inserted near 

 the forehead ; the mandibles toothed inter- 

 nally; the maxillary palpi very small, nearly 

 conical, and two-jointed, with the extremity 

 of the abdomen prolonged into a horn, and 

 the ovipositor exserted and formed of three 

 tlireods. These insects are of large size, and 



SIREX OIOA8. 



generally inhabit pine forests in cold and 

 mountainous countries, and produce during 

 flight a buzzing noise like that of the Hum- 

 ble-bees. In those countries they appear, in 



certain seasons, in such abundance that they 

 become objects of popular dread. The larvse j 

 have >ix feet, with the posterior extremity | 

 of the body terminated iu a point ; they live ; 

 in wood, where they spin a cocoon and j 

 undergo their transformations. The Sirex j 

 pigus has sometimes, though rarely, occurred i 

 in this country, and is as large as a Hornet. 



SISKIN, or ABERDEVINE. (Carduelis 

 gpinus.) A song-bird, very similar in colour | 



d general appearance to the green variety > 

 of the canary, though somewhat more dusky ! 

 on the back and head. It is a lively and ' 

 persevering songster ; soon becomes familiar 



6T8KIN OB ABERUITINE ; M4I.R AND FBMiLF. 

 (CiRDUFI.IS SPINC8.) 



when in captivity, and is often paired with 

 the canary-bird. It breeds in Sweden, 

 Norway, the north of Germany, and some- 

 times in the Highlands of Scotland, visiting 

 England only in the autumn and winter. 

 In most places they are migratory, but do 

 not seem to observe regular periods, as they 

 are sometimes seen in large, and at other 

 times in very small numbers. Buffon ob- 

 serves that these immense flights happen 

 only once in the course of three or four 

 years. They conceal their nest with much 

 art. In some parts of the south of England 

 it is called the Barley-bird, being seen about 

 that seed-time ; and in the neighbourhood 

 of London it is known by the name of the 

 Aberdevine. 



SITTA. The Linnaean name of a genns 

 of birds, of which the Nuthatch is the type. 

 [See NUTHATCH.] 



SKATE. (Raia bails.) This fish, the 

 true Skate, in proportion to its bulk, is the 

 thinnest of any of the RaiadcE as well as the 

 largest, some being known to weigh near two 

 hundred pounds. The breadth of the body 

 is to its length nearly as four to three. The 

 nose is conical ; and above the eyes there is 



