CHONDROSEPIA. 



CHRYSI'DID/E. 



gill-opening, and in the latter they have several generally five 

 These orders are divided into families and genera, as follows : 



Order 1. Chondropteryijii. With free Gills. 

 Family 1. Sturionida (Sturgeons). 

 Genus 1. Accipenser. 

 2. Spatularia. 

 Family 2. Chinueridie. 



Genus 1. Chimcera. 



Order 2. C/tondropteryijii. With fixed Gills. 

 Family 1. Srfualida; (Sharks, &c.). 



The principal genera are : 

 Squalus. 



Zygoma (Hammer-Headed Sharks). 

 Squat ina (Angel-Fish). 

 Pruslei (Saw-Fish). 

 Family 2. Raiida;. 



Principal genera : 

 Torpedo (Electric Rays). 

 Raia (Skate-Fish). 

 Trigon (Sting-Rays). 

 Mylobatet (Eagle-Ray). 

 Cepfialoptera. 



Family 3. Pleromyzidie (Lampreys, &c.). 

 Genus 1. Pteromyzon. 

 2. Ammocaste. 

 3. Goitrobranchvt. 

 4. Amphioxut (Branchiosloma). 

 CHONDROSE'PIA, Leukard's name for a genus of Ceplialopoda, 



. 



CHONDRUS. [Ato*.] 



CHONDRUS, a Pulmoniferous Mollusk. [PtJLMOBBANcniATA 1 



CHORDARIACE.E. [ALCJJ.] 



CHOUGH. [CORVID*.] 



CHHISTIANITE, another name for Anorthile. [AuoBTHiTE.] Ithas 

 also been applied to a mineral allied to PkMippsite. [PHILLIPPSITE 1 



CHRISTMAS-ROSE. [HELLEBOBUS.] 



CHRISTOPHER, HERB. [Ac-TJiA.] 



CHROMIRON. [CHROMIUM.] 



CHRO'MIS, a genus of Fishes. [LABRID.E.] 



CHROMIUM, a Metal. It does not occur pure in nature. The 

 following are the most important ores containing Chromium : 



Chromate of Lead. Red Lead. Occurs massive and crystallised. 

 Primary form of the crystal an oblique rhombic prism. Colour deep 

 orange-red. Lustre adamantine, sometimes translucent, rarely trans- 

 parent. Specific gravity, 6. Hardness, 2'5 to 3. Brittle; streak 

 orange-yellow. Cross-fracture uneven, passing into conchoidal, with 

 a splendent lustre. With the blowpipe it crackles and melts into a 

 grayish slag. Soluble in nitric acid ; solution yellow. Occurs in the 

 gold mine of Berezof in Siberia, in the Ural, and Brazil. 



When pure it is composed of 



Chromic Acid ...... 3171 



Oxide of Lead ....... 68"29 



100 



Massive varieties amorphous ; structure columnar, granular. 

 Subsesquichromate of Lead. Monuchroite. Occurs massive and 

 crystallised. Form of the crystal imperfectly described. Colour red. 

 Lustre resinous ; translucent on the edges. Specific gravity, 575 ; 

 very soft. Powder tile-red. 



Fuses by the blowpipe into a dark mass. Occurs with Chromate of 

 Lead in the Ural. It is composed of 



Chromic Acid 23'31 



Oxide of Lead 76'69 



100 



Chromate of Lead and Copper. Vauquelinite. Occurs massive 

 and in minute crystals. Primary form an oblique rhombic prism. 

 Colour black or greenish-black. Lustre adamantine, nearly opaque. 

 Specific gravity, 5'5 to 578. Hardness, 2'5 to 3. Streak greenish. 

 Fracture uneven. 



Before the blowpipe it fuses into a dark gray globule of metallic 

 lustre, surrounded with beads of metallic lead. 



The massive varieties are amorphous, botryoidal, reniform. 

 Structure compact, fine granular. 



Found with Chromate of Lead in Siberia. 

 Composed of, according to Berzelius, 



Chromic Acid . ; . . . .28-33 



Oxide of Lead 60'S7 



Oxide of Copper 10'8 



100 

 Chromate of Iron. Chromiron. Occurs massive and crystallised. 



Crystal the regular octahedron. Colour blackish ; lustre imperfect 



metallic; opaque. Hardness, 5'5 ; brittle. Specific gravity, 4'321. 



Streak brown. Fracture uneven, imperfect conchoidal. Not attracted 



by the magnet. Cleaves parallel to all its planes. 

 HAT. Hisr. r>iv. VOL. I. 



Analysis of the crystals from Baltimore, by Dr. Thomson : 



Green Oxide of Chromium . . . . 52'95 



Peroxide of Iron 29 -24 



Alumina 12'22 



White matter 3-09 



Water 070 



A trace of Silica . 



The massive is amorphous, with a granular or compact structure. 

 It is found in the island of Unst, in Scotland, and sometimes inter- 

 spersed with green oxide : it occurs also in France and in North 

 America, especially near Baltimore. Oxide of Chromium has been 

 observed in some aerolites. 



CHRYSALIS. [PUPA; INSECT.] 



CHRYSANTHEMUM, a genus of plants belonging to the natural 

 order Composite and the sub-order Corymbiferce or Asteracae. This 

 genus is known by the receptacle being without scales, the heads of 

 flowers heterogamous, the flowers of the ray containing pistils and 

 those of the disc both stamens and pistils ; the involucre hemi- 

 spherical ; the fruit terete, without wings, no pappus ; the flowers of 

 the ray ligulate, those of the disc tubular. The species are very 

 numerous in the temperate parts of the earth. 



C. Sineme is most extensively cultivated in our gardens. [CHRYS- 

 ANTHEMUM, in ARTS AND Sc. Div.] 



There are two British species : 



C. leucanthenmm, Ox-Eye or Ox-Eye Daisy. It is very common in 

 our fields, and is known by the large white ligulate flowers of the ray, 

 and the yellow tubular ones of the disc. 



C. Scgelum, the Corn-Marigold. It is common in corn-fields, and is 

 easily distinguished from the last species by the flowers of the ray 

 being yellow instead of white. 



CHRY'SAOR, one of the numerous genera into which De Moutford 

 divided the Belemnites. 



CHRYSA'ORA. [ACALEPH.*:.] 



CHRYSI'DID^E, a family of Hymenopterous Insects of the section 

 Pupivora. Distinguishing characters: No nervures to the under 

 wings; terminal segments of the abdomen forming a jointed retractile. 

 ovipositor ; abdomen of the females with only three or four distinct 

 segments, concave or flat beneath ; antennae 13-joiuted in both sexes, 

 and geniculated ; mandibles slender, curved, and pointed ; maxillary 

 palpi filiform, generally longer than the labial palpi, and 5-jointed ; 

 the labial palpi are generally 3-jointed. 



The Chrysididce are most of them, if not all, of parasitic habits, 

 that is to say, they seek the nests of other insects where they deposit 

 their eggs to the destruction of the rightful owners ; each species of 

 this family apparently confining its attacks to the nest of some other 

 bymenopterous insect, and generally selecting those of the same 

 species. They are all of brilliant colouring, very active, and fly about 

 in the sunshine ; some are seen upon flowers, and most of them upon 

 old walls, palings, and sand-banks. Some of these species are called 

 Ruby-Tail Flies. 



Chnjsii ignita will afford a good illustration of this family. This 

 insect is rather less than half an inch in length, has the head, thorax, 

 and legs of a rich blue or green colour, and the abdomen of a burnished 

 golden-copper hue ; thia part is truncated at the apex, and furnished 

 with four little spines. 



It will be perceived that the above is a description of a little four- 

 winged fly, which so often attracts our notice from its brilliant 

 colouring, and is so common on our garden walls when the sun is ou 

 them. This little insect is in constant motion, for if it ceases 

 running or flying for a moment its little horns still keep up their 

 vibratory motion. If we watch one of these insects for a short time 

 we perceive that it thrusts its head into every little hole in the brick-' 

 vork ; it is then searching after the nest of a wasp-like insect which 

 juilds in these situations. 



Tin' principal genera comprised in the family C/irysididai are 

 Paaorpa, Ckrysis, Slilbum, Jledicrum, Elampus, and defies. An 

 account of the habits of one of the species of Pa>u>rpea is given 

 under the head BEMBEX, where the habits of B. rustrata, are given, 

 that being the species whose nests are subject to the attacks of the 

 anorpe which we are about to describe. 



The genus Panorpes is distinguished from the other genera above 

 mentioned principally by the elongated maxilla and labium, which 

 appear like a proboscis, and the palpi being very small and two- 

 ointed. P. carnea is about half an inch in length, and considerably 

 jroader than the C/iry/ria iynita (nbove described) ; the head, thorax, 

 and base of the abdomen are of a blue-green colour ; the remainder 

 jf the abdomen and the legs (with the exception of the thighs, which 

 .re blue) are of a reddish-yellow colour. It is found in various parts 

 T Europe. 



The characters of the genus Chrytii are : Maxillary palpi 

 jointed, and longer than the labial ; labial palpi 3-joiuted ; thorax 

 lot narrowed in front ; labium rounded. About six or seven species 

 f this genus are natives of England. C. bidtnlata is rather less than 

 \ ignita, and differs from that species in having the thorax as well 

 9 the abdomen of a rich copper-like hue : the latter however has tho 

 pex blue. C. cyanea is entirely of a blue colour. 



3 v 



