SIMPLEGAS SIREN. 



are decandrous, with one pistil ; the carpels are two- 

 salved, and one-seeded. In our stoves they thrive 

 in loam and heath mould, and are propagated by 

 cuttings. 



SIMPLEGAS. A fossil mollusc allied to the 

 Ammonites, from which it is distinguished by the 

 septa being plain, and not sinuous. 



SIMULIUM (Latreille). A genus of small 

 dipterous insects belonging to the family Tipulides, 

 having the eyes large and internally notched, the 

 ocelli obsolete, the antennas short and eleven-jointed, 

 and the proboscis pointed and perpendicular. These 

 are minute insects like midges, which abound to a very 

 great degree in damp situations, where they attack 

 the inhabitants in the same manner as the real gnats 

 (Culicidce] ; indeed in South America it would appear 

 from the recent work of Messrs. Pohl and Kollar, 

 that the same name mosquito is given to both the 

 Culex and the Simulium. In some of the Northern 

 parts of Europe their irritating powers are so great, 

 that the inhabitants are compelled to cover them- 

 selves with a coating of grease. The type of the genus 

 is the Simulium reptans, Latreille. In North Ame- 

 rica they are distinguished from the mosquito under 

 the name of the black fly. 



SIN APIS (Tournefort). A genus of hardy an- 

 nual herbs, several of which are cultivated for their 

 pungent seeds, of which the common condiment 

 mustard is manufactured. The flowers are tetran- 

 drous, and belong to Cruciferes. 



SINNINGIA (Nees). A genus of South Ame- 

 rican nnder-shrubs belonging to the natural order 

 GesneriecE. This is a succulent genus, and succeeds 

 in any rich dry soil ; and young cuttings planted in 

 the same soon make roots. 



SINODENDRON (Fabricius). A genus of 

 coleopterous insects, belonging to the family Lu- 

 canidce, distinguished by having the body elongate 

 and cylindric ; the head of the male armed with an 

 erect horn ; the antennae elbowed, ten-jointed, the 

 first joint being very long, and the three terminal 

 joints forming a deeply serrated club ; the legs short, 

 with the tibia) spined. The genus comprises a single 

 British and several exotic species, the former being 

 the Scarabacus cylindricus of Linnaeus. This species 

 is found in Normandy in the rotten trunks of apple- 

 trees, and in Flanders jn decayed beech-trees. In 

 England it appears to be more frequent in the ash 

 and willow, as we learn from Stephen's British Ento- 

 mology, and the following observations of the Rev. 

 W. T.'Bree, published in the Gardeners' Magazine : 

 A living ash-tree, standing on his premises, was 

 blown down on the 3rd December, 1832. Its trunk, 

 for about eighteen feet up from the part that had 

 been level with the ground, was hollow and decayed 

 at the centre, and afforded some twenty or thirty 

 good barrow-loads of rotten wood. Throughout 

 this carious portion of the tree there occurred nume- 

 rous individuals, both in the larva and imago state, 

 of the Dorcus parallelopipcdus (another species of 

 the Lncanid<e\ and of its usual associate, the Sino- 

 dendron cylindricum, but not a single pupa was dis- 

 covered ; they had perforated it in all directions. 

 Many were found pursuing their occupations in the de- 

 cayed timber at the distance of eighteen feet from the 

 ground, to which height they must have worked their 

 way from the bottom. He was satisfied that they 

 did not commit any injury on the living or sound 

 wood, attacking such only as they found far gone in 



a state of decay. This insect is of a black colour, 

 and varies in length from one half to three-fourths of 

 an inch. 



SIPHONARIA (Lamarck). A patelloid shell, 

 elliptical, the summit well marked, a little on the 

 left, posteriorly, a canal or gutter on the right side, 

 the muscular impression in the form of a horse-shoe, 

 the right lobe divided in two by the canal. 



SIPHONIA (Richard), the S. Cahuchu is the 

 Indian-rubber tree, called Jatropha elastica by Lin- 

 naeus. The flowers are monoecious, and belong to 

 Euphorbiacece : cuttings. 



SIPHONOBRANCHIATA constitute the first 

 order of the second class Paracephalophora in De 

 Blainville's Malacology. The leading characters of 

 these molluscs is their organs of respiration being 

 constantly formed by one or two pectinif'orm branchia, 

 obliquely situated on the anterior part of the back, 

 and contained in a cavity whose upper coating is 

 provided with a tubular canal more or less elongated, 

 and attached to the columella. The first family of 

 the order is the Siphonostomata genus Murex of Lin- 

 riseus, and includes the genera Murex, Pleurotoma, 

 Rostellaria, Fusus, Pyrula, Fasciolaria, Turbinclla, 

 Columbella, Triton, Ranella. The second family the 

 Entomostomata, is Linnaeus' genus Buccinum ; it in- 

 cludes the Cerithium, Mclanopsis, Planaris. Subula 

 Terebra, Eburna, Buccinum, Harpa, Dolium, Cassi, 

 daria, Cassis, Ricinula, Cancellaria, Purpura, Concho- 

 lepas. The third family, Angyostomata, includes th 

 Strombus, Conus, Terebellum, Oliva, Ancillaria, Matra* 

 Valuta, Marginella, Peribolus, Ct/prcea, Ovula. 



SIREN. A genus of Batrachian reptile, and the 

 last both of the order and the class in the arrange- 

 ment of the animal kingdom by Cuvier. To this 

 place in the system it is unquestionably entitled, as 

 the animals composing it partake of the characters, 

 and even of the forms, both of reptile and of fish, 

 though that of reptile, on the whole, predominates. 



Animals of this genus are the only known ones 

 that are true Amphibia, furnished with both lungs and 

 gills, either of which they can use at pleasure. The 

 characters are : the body elongated, and nearly in the 

 form of that of an eel ; three tufts of gills ; no hind 

 feet, and not the least vestige of a pelvis ; the 

 vertebrae of the spine very numerous, and articulated 

 something in the manner of those of a fish, that is, 

 with the proximate ends concave, and united by 

 cartilage which forms the joint, so that there is no 

 motion of bone upon bone, and there are only eight 

 ribs upon each side. The body of the siren may 

 thus be regarded as consisting of only a thorax and a 

 tail ; the former being that of a reptile, and, as such, 

 furnished with feet ; and the latter that of a fish, 

 producing fins only. The head is flattened, the 

 muzzle blunt, the opening of the mouth small, the 

 eye very small, and the ear hidden in the skin ; the 

 lower jaw is furnished with teeth all round, but the 

 upper jaw has none, though there are several rows 

 upon two plates, one on each side of the palate. 



There have been many disputes respecting the 

 siren, and not a few have been disposed to regard it 

 as the tadpole of the salamander. But Cuvier has 

 demonstrated that the gills are part of the permanent 

 structure of the animal, and not temporary organs, 

 like the gills of tadpoles, to fall off or be absorbed 

 when the animal comes to maturity ; and he remarks 

 that some of the sirens are much larger than any 

 salamander even in the full-grown state. This struc- 



