929 



CHALYB.EUS. 



CHAMACEA. 



930 



the Sponges and some of the Infusoria are found in the Chalk. 



[FORAMIXIFERA.] 



Of the Zoophytes, the Pulyzoa have been found in the greatest 

 abundance in the Cretaceoxis beds (Neocom ten) of the continent of 

 Europe. They have been most elaborately described by D'Orbigny. 



[POLYZOA.] 



The Echinodermata abounded during the period of the deposit of 

 the Chalk, and afford a larger number of interesting forms than occur 

 in any other formation. The genus Marsapites affords an instance of 

 the passage amongst these creatures from Encrinites to the Spatangi. 

 Numerous species of Spatangus, Cidaris, Goniaster, and other genera 

 of this family are found. The spines of the Echinid'x are often found 

 separated from the shell. [ECHINODERMATA.] 



Several forms of Crustacea belonging to the more highly-developed 

 sections of the family are found. 



The A/oil tuea are abundant. Of these the forms of Brachiopoda, 

 especially Tenbratula, are numerous. The genus Radiates, which 

 D'Orbigny refers to the Brarhiopoda, is in some respects the most 

 interesting of the Mollusca of the Cretaceous Formations. The 

 species are most abundant in the Cretaceous series of the South of 

 Europe. The Cephalopodous Mollusca were very numerous and 

 varied in their forms during the Cretaceous period. The following 

 genera are found : NautUm, Ammonites, Crioceratites, Turrilitex, 

 Scaphitet, Baculties, Hamites, and others. 



The Fishes of the Cretaceous system are numerous, and belong to 

 the Placoid, Ganoid, Ctenoid, and Cycloid types. Of the last two the 

 genera are fewer in number than of the first two. The Ctenoids and 

 Cycloids however appear in the Cretaceous system for the first time, 

 and are interesting on this account. 



The Reptiles, though not so numerous in the Cretaceous period 

 as in that which immediately preceded it, are nevertheless numerous. 

 It is here that the Mototauria has been found, also several species of 

 Plerodaetyli, and the remains of the Iguanodcm and Ichthyosaurus, 

 with species of Ckelonia. 



CHALYBvEUS, a genus of Birds, separated by Cuvier from the 

 Cassicans of Buffon ; Barita of Cuvier. The bill has the same form 

 as that of the Cassicans, but it is a little larger at the base than that 

 organ is in the last-named genus, and the nostrils are pierced in a large, 

 membranous space. 



The species come from New Guinea, and are remarkable for the 

 metallic tints of their plumage. 



Example, Chalybaut paraduiriu. This richly-plumed bird is the 

 Paradisea riridis of Gmelin ; Le Calybe 1 de la Nouvelle Quince of 

 Buffon ; Le Grand Chalybd of Le Vaillant ; Oiseau de Paradis Vert of 

 S.iimcnit; Paradisea chalybta, Blue-Green Paradise Bird, of Latham ; 

 Cracticas chalybeus of Vieillot ; Barita viridis of the first edition of 



Blue-Green Bird of Paradise (Chalylms paradiiceut). 



the ' Regne Animal ' (where it was placed under the Casaicans, Barita), 

 and Cltnliiliifiu paradisirus of the last edition. It is the Mansincme 

 of the Papuan tongue, according to Lesson, who thus writes on the 

 subject from personal observation : " Among the numerous skins ol 

 birds of paradise which the inhabitants of New Guinea brought daily 



NAT. HIST. DIV. VOL. I. 



on board, I found some Clialybai deprived of their feet, and run 

 through with a stick like the skins of the true birds of paradise. 

 Afterwards we often procured in our shooting parties a bird which 

 does not vary from that of which we speak, except in having a more 

 sombre and tarnished plumage, there being no difference in the pro- 

 portions of the body, bill, wings, or tail. We regard it as a slight 

 variety of the CalybfS of authors ; for those that we saw which were 

 adult and in complete plumage, did not permit us to think that they 

 could be Chalybcei before or after their moult. The total length of 

 our Chalybaut was 14 inches 6 lines (French). The bill differed not 

 at all from the ordinary C/ialybaus. The head is large, and the tail, 

 6 inches in length, is rounded by the disposition of the feathers, as in 

 the preceding. The plumage is entirely bluish metallic green, 

 having none of the iridescent, varying, and violet tints. The feathers 

 of the ueck and abdomen are not figured (gaufre'es), nor powdered 

 (sabl^es) with gold and silver on a green and blue ground of 

 burnished steel, as it were (d'acier bruni), like the Chalylmus ; but 

 the plumage that covers these parts has a uniform tint, having the 

 brilliancy of specular iron (fer spe'culaire) following the reflections 

 of the light. The feathers which cover the head and neck are short, 

 close set, and velvety. The nostrils are partially closed by a mem- 

 brane covered by the frontal feathers, which advance on each side 

 of the edge (arete) of the bill, which is black. The iris is coral-red, 

 and the legs are of the same colour as the bill. Their shanks (tarses) 

 are covered with large scales (e'cussons), and their toes are strong, 

 furnished with compressed claws, flattened above, and crooked. 



" The Chalybceu* lives solitary in the forests of New Guinea. We 

 often saw it perched in the great trees, where it seeks for fruits. 

 Its manners appeared to have great analogy to those of the crows." 



CHALYBEATE WATERS. The water of springs charged with 

 any of the salts of iron are called Chalybeate. [SPRINGS, MINERAL.] 

 CHAMA. [CHAMACEA.] 



CHAMA'CEA, or CHA'MID^E, a family of Conchiferous Mottusca, 

 the third of the Acephalous or Headless Testacea, according to Cuvier, 

 who places them between -his Mytilacea (Mussel-like Testaceans), and 

 his Cardiacea (Cockle-like Testaceans). 



Under the Linnxan genus Cliama many heterogeneous forms were 

 assembled ; and as G. Sowerby observes, " in his arrangement regular 

 and equivalve shells are placed with such as are irregular and equi- 

 valve ; free shells with others that are attached to marine bodies ; 

 and shells which have two distinct muscular impressions with others 

 which have only one." 



Bruguitre first divided this genus, and Lamarck carried out the 

 reformation. The latter makes the Cham'uke to consist of the genera 

 Dieeras, Chama, and Elheria, placing Tridacna and I/ippopvs under 

 his Tridacnees, the first section of his second order Cnchiferes Mono- 

 myaires. 



Cuvier made the Camace'es consist of the genera Chama, Tridacna, 

 Hippoput, Chama (Brug.), Kteras, and Isocardia. 



The genus Chama has the following characters : The valves are 

 irregular, inclining for the most part to the orbicular shape, unequal, 

 generally foliated or spined externally, and adherent. The umbones 

 are distant, unequal, and curled or involute. The hinge consists of 

 one thick oblique somewhat notched tooth, inserted into the groove 

 of the opposite valve. There are two muscular impressions, and they 

 are distant and lateral. The ligament is external, and divided into 

 two portions at its posterior extremity. The animal (Psilopus of 

 Poli) is less irregular than the shell, and cordiform, or heart-shaped; 

 the two lobes of the mantle unite posteriorly, and in the commissure 

 are two very short ciliated siphons, like those of Isocardia. Upon the 

 abdominal mass a small cylindrical truncated bent foot rises. The mouth 

 is small, and is furnished on each side with a pair of somewhat square 

 and obliquely-truncated palpi. Deshayes states that all the indivi- 

 duals of the same species adhere by the valve of the same side, and 

 that the umbones curve in the same direction. 



Broderip, in the first volume of the ' Transactions of the Zoological 

 Society of London' (1834), where he describes several new species 

 brought home by Mr. Cuming, says, " The shells are attached by their 

 external surface to submarine bodies, such as corals, rocks, and shells, 

 and have been observed at depths ranging from points near the sur- 

 face to 17 fathoms. These shells appear to be subject to every change 

 of shape, and often of colour, that the accidents of their position may 

 bring upon them. Their shape is usually determined by the body to 

 which they are fixed ; the development of the foliated lamina; which 

 form their general characteristic is affected by their situation ; and 

 their colour most probably by their food and by their greater or less 

 exposure to light. The Chama that has lived in deep and placid 

 water will generally be found with its foliations in the highest state 

 of luxuriancy ; while those of the individual that has borne the 

 buffeting of a comparatively shallow and turbulent sea will be poor 

 and stunted. Lamarck has divided the species into two sections, 

 namely, first, those the umbones of whose shells turn from left to 

 right ; and, secondly, those whose umbones turn from right to left. 

 M. Sander Rang, in his ' Manual,' has adopted this division, to which 

 I cannot subscribe, because it will not bear the test of examination. 

 Two remarkable instances are now well known of regular bivalves of 

 the same species, in which one specimen may be regarded as being the 

 reverse of the other, namely, Lucina Childreni, and an inequivalve 



3 o 



