(THORN. 



CUNITA. 



IN 



....... . . . : 



and beam UM active and *v*a dangerous qualities of tbose plants, 

 from which tbe Cwmmber iteelf i* not exempt : only its bitterness 

 i. ileini*il by tb* peeolUr eultivalioci of that plant Tb* seeds of 

 >BM kinds yWld nil ; and thoee of CWvstw ilomonlira an said to 

 U ground inti a kind of ines! [CcrVMU; CrrrmiiTA; BsToniA ; 



CTDDKS. [Mii AXOCS-] 

 I >WEED. [Kiiauti.) 



I LEX. fCcucilwa.) 



i ri.I C1DES iLatreilUl. a family of Dipterous Insect* of the 

 section JVpJUcrr*. It has the following characters : Proboscis long 

 and sledr, projecting forwards, usually straight, terminated by two 

 litU* lip-bke appendages ; sucker composed of six alender bristle-like 

 member.; palpi 5 jointed, grnwrmlly elongated; antenna; filiform, 

 emend with hairs in tbe male sex resembling little plumes ; eyes 

 eaaUfUou* ; no ocelli ; wings inclined, lying close to the body when 

 at net, and having on* marginal and two sub-marginal cells. 



Tbe CWirirfsf. according to Latreille, constitutes the first family of 

 Diptaron* Insect*, and is the same group as that designated by Lin 



i Ctdfi. It is divided into three genera, distinguished principally 

 by tbe following rhsncton: 



AoojJirt'i (Mrigen.) Palpi equal in length to the proboscis in 

 botherxe*. 



Cater. Palpi of the males longer than the proboscis, and in the 

 female* very short 



(fdm. Palpi shorter than the proboscis in both sexes. 

 We an but too well acquainted with the torment inflicted by the 

 iiisiiuls of this tribe, which an known in this country by the name of 

 Onatx ; an called in France Cousins ; and in America Mosquitoes. 



Tbe pain and irritation are caused by their piercing the skin to 

 feed upon tbe blood (by means of the little bristles forming part of 

 tbe proboscis), and injecting at the same time a poisonous fluid. It is 

 said tbe females alone arc the persecutors. 



Tbe humming noise accompanying their flight is produced by the 

 vibration of their wings. Gnats' seldom appear during the day-time, 

 except in thick woods, and they always abound most in damp situa- 

 tions, a circumstance owing to the habits of their lamr, which reside 

 in stagnant water*. 



Tb* female Onat deposit* her eggs (which amount to 200 or 300 in 

 a year) one by one : and as they are deposited they ore joined together, 

 mod form a little raft, which floats on the surface of the water. The 

 eggs an hatched in about three days' time, and produce little greenish 

 lamr, which have a distinct head and lengthened body, composed of 

 numerous segment*. The head is furnished with two ciliated organs, 

 which an in constant motion. This motion appears to be for the 

 purpose of creating a current, by which means minute animalcule}, or 

 other substance* which may constitute the food of the animal, are 

 dnwn into the mouth. Two other appendages, furnished with tufts 

 of hair, appear to co-operate with the former for this purpose. 



Tbe breathing apparatus. of the larva consists of a tube, terminated 

 by radiating seta situated at the apex of the body ; through this tube 

 tbe air is conveyed to tbe trachea*, and for this purpose it is brought 

 to tbe surface of the water, so that the animal is then in an inverted 

 position. Then is another apparatus also, situated at the tail of the 

 animal, opposed to tbe breathing apparatus, which servos as a fin, and 

 eosblei the larva to swim and dive with considerable velocity. 



These Urns an full grown in about fifteen days' time ; they next 

 assume tbe pupa state ; the animal then appears to have a rounded 

 form, owing to the apex of the body being recurved. It still inhabits 

 tbe water and i* active ; the position of its breathing apparatus is 

 however altered, it bring now situated on the anterior part of the 

 body, sod consist* of two little tubes, which, as before, are applied to 

 tb* surfac* of tb* water for the reception of air. When about to 

 assuror tb* imago state, the skin which covered the pupa being 

 IcossDsd from tbe animal within, and the space between the two being 

 occupied with air, it floats upon the surface of the water; the Onat 

 breaks through tbe upper part, and stands on the skin it has quitted, 

 and which now serves as a little boat, upon which it floats until it has 

 attained strength to fly. 



Osfarimi(UnB.). the Common Onat, i* lew than a quarter of an 

 iswb Isl length ; tb* palpi and antenna; are brown ; the thorax is of a yel- 

 lowish brown, with two darker lines ; the abdomen U of a pale gray 

 colour; tb> legs an brown, and tb* base of the thighs yellowish. 



Tb* insert which I* so troublesome in the West Indies, the Mos- 

 quito (Oultx IrospUfo), U not quite so large as the Common Onat 

 It* proboscis i* black ; tb* palpi an spotted with white; the head 

 and thorax *n spotted with silvery white, and the Utter has a curved 

 band of UM *Bin* bne. Tb* edges of the segment* of the body are also 

 of a silver lik* colour. 



CULM, tb* stem or strsw of grassc*. 



CCLTIROSTRE8, a DUD* given by Cuvier and others to a f.imily 

 of Birds, consisting of those species which were united under the genus 

 Ar4t* by Linnsraa, and whose bill is Urge, long, and strong, and most 

 <ros^Doiat*ds}*o,sach a* Cranes, Herons, Storks, Ac. [ARDKA.] 

 CUMBRIA X ROCKS. Professor Sedgwick ha* given this term to 

 UM low*** series of Slatv Rook* which appear in the ramre. of Skiddaw 

 K.U in Cumberland. Tb*y U* below tb* green slaty 



rocks of Scam-fell and the Old Han, which the same writer regards as 

 coeval with the strata of Snowdon, and ranks under the title of 

 Cambrian. [CAMBRIA* ROCKS.) 



The succession of rocks, as pointed out by Professor Sedgwick in 

 the Cumberland hills, is as follows : 



1. Skid. law Slate, usually without fossils, but containing Graptolittt 

 in one locality. 



2. Coniston Limestone, abounding in fossils. 

 S. Coniston Flagstone and Grit. 



These rooks find their representatives in those called Cambrian in 

 North Wales. Those Utter rooks an included by Sir Roderick 

 Miiivhison in his ' Silurian System.' As the nomenclature of these 

 rocks is still a dispute! question, we subjoin the account of them 

 published by Mr. Jukm, in his work on ' Physical Geology.' 



"Cambrian or Cumbrian Rocks. The word ' rocks is used here 

 instead of ' system,' or ' formation,' because we cannot yet precisely 

 toll the value of the Cambrian division. Cambrian means the rocks 

 of Wales ; Cumbrian those of Cumberland and Westmoreland. In 

 Wain these rocks consist of certain thick sandstones, gritstones, and 

 conglomerates, with Intel-stratified beds of green or green and imq.1.- 

 late*. It U in the uppermost of the slate beds of this Cambrian 

 group that the great Penrhyn and Llanberris slate quarries are 

 opened. They contain no fossils. These rocks are found to have a 

 thickness of upwards of 20,000 feet in some places in North Wales ; 

 but as the base of them is never exposed we know not how much 

 greater thickness they may possess, nor what is btjlow them. One 

 portion of this division has boon provisionally called the ' Barmouth 

 and Harlech Sandstone Group.' Their upper boundary is a purely 

 arbitrary line along the top of a certain set of beds drawn by the 

 officers of the Geological Survey of Great Britain, under the direction 

 of Sir H. T. He la Beche, C.B. ; their reason fur drawing it being 

 simply that no fossils have as yet been found below that line, whereas 

 fossils are pretty abundant in many places above it. It must not be 

 forgotten that Professor Sedgwick (of whose peculiar department we 

 are now speaking, he being the one geologist who has single-handed 

 done far the most to unravel the structure of these older rocks) 

 dissents from this placing of the boundary of the Cambrian Rocks ; 

 and himself places it much higher, so as to include the beds we shall 

 subsequently speak of, as Lower Silurian, dividing his system into 

 Upper and Lower Cambrian. There con be no doubt that if we 

 neglect the fossils, and look only to the physical structure and position 

 of the rocks of Wales, Professor Sedgwick is right. There con be no 

 reason for drawing the boundary where it has been drawn, and along 

 no other geological horizon in North Wales, except the fact that 

 fossils have been found in all the rocks above that line of division, and 

 in none of those below. Whether they may not hereafter be found 

 is another question. If we go to Cumberland, Professor Sedgwick 

 there describes the Cambrian, or, as he there calls them, Cumbrian 

 Rocks, as likewise consisting of upper and lower, and gives the 

 following abstract of them : 



{Coniston Flagstone . 

 Coniston Limestone 

 Slates and Porphyry 

 Cumbrian, Lower Skiddaw Slate 



F**t 

 . 1500 

 300 



. 10,000 

 6000 



He describes these however as all fossiliferoua, which, by the rule 

 lately mentioned, would exclude them from being considered as 

 Cambrian at all, more especially as the fossils of the upper beds ore 

 such as palaeontologists seem agreed to consider of Silurian age. It 

 is highly probable that tbe Skiddaw Slates are of the same age 

 as the Barmouth and Harlech Sandstone Group of North Wales, 

 which likewise contains the best roofing-slates of that country. In 

 that case, according to the classification adopted by the Geological 

 Survey, the Skiddaw sUtes would be considered Cambrian, and all 

 above them as Silurian. The reader will gee from these statements 

 that this part of the classification of the stratified rocks is far from 

 being settled. There is however no dispute about the things 

 themselves; the rocks are all known, and their order completely 

 ascertained; the uncertainty is merely as to the name by whii-'h 

 certain portions of them shall be called." [WALKS, OEOLOOT or, in 

 Gsoo. 



CUMINOIA. [CosctiACEA.] 



CUUINUM, a genus of Plant* belonging to the natural order 

 I'mMliferir. It has 5 calyx teeth, which are lanceolate, setaceous, 

 unequal, and permanent The petals ore oblong, emarginate, erect, 

 spreading, with an indexed lobe. The fruit is contracted at the side. 

 The ridges of half-fruits wingless ; the primary filiform, minutely 

 muricated, the laterals forming a border, the secondary more promi- 

 nent and aculeated ; the channels under the secondary ridges with 

 one vitta in each. The species are annuals, with multifid leaves, 

 having setaceous divisions. The flowers are pink or white. 



CUMMINOTONITE, an American Mineral belonging to the Horn- 

 blende series. It is fibrous, of an ash-gray colour, with a slight silky 

 lustre. H U found at Cummington and Plainfield, in Massachusetts. 

 (Uana, Mineralogy.) 



CUNITA, a genus of Plant* belonging to the natural order 

 Labiatir. It has a 13-nerved calyx, ovate, tubular, equal, 5-toothed, 

 the throat villous inside. The corolla having the tubs equalling the 



