C Y A M U S C Y C A D E JE. 



1225 



best possible manner to their different and individual 

 exigencies. 



CYAMUS (Latreille). A genus of crustaceous 

 animals belonging to the section Edriophthalma and 

 order Lasmodipoda, and having for its type a curious 

 species, which is found upon the bodies of living whales, 

 being the Oniscus ceti of Linnaeus. This genus consti- 

 tutes a distinct division in the order to which it belongs, 

 to which Latreille has given the name of Ovafia, oval 

 bodied, in order to distinguish it from the other divi- 

 sion of which CAPRELLA (which see) is the type, and 

 which is remarkable for the long and slender form of 

 the body. These animals were considered by M. 

 Savigny as being nearly allied to the Pi/cnogonida, 

 and forming with them the passage between the crus- 

 tacea and arachnida. The body is composed of a 

 small somewhat oval-formed head and six transverse 

 segments, the abdomen being very minute and rudi- 

 mental. The head is furnished with two moderate 

 sized and two minute antenna?, with an oral apparatus, 

 concerning the various organs of which authors are 

 somewhat at variance. At the base of each of the 

 smaller antennae is a small depressed cup-like spot 

 covered with a membranous substance, and which 

 has been regarded as the organ of the sense of hear- 

 ing. The eyes are two in number and granulated, 

 although Savigny calls them " yeux lissees," whilst 

 the yeux composees, which he mentions between the 

 antennae, are not discernible. The legs, or the limbs 

 representing those organs, are of varied form, the first 

 pair being slender and terminated by a claw and a 

 moveable ringer, the second, fifth, sixth, and seventh 

 pairs are greatly dilated and terminated by a large 

 joint, and a moveable recurved finger ; but the most 

 ' curious portions of the animal are the organs repre- 

 senting the third and fourth pairs of legs, and which 

 consist in two or four pairs of long and slender ap- 

 pendages, which have been considered to be organs 

 of respiration ; these are, moreover, furnished on the 

 underside of the body of the females with four large 

 plates serving as a pouch for the reception of the eggs. 



We are indebted to M. Rousse! de Vanzeme 

 (whose memoir upon another whale parasite, Cetochilus 

 australis, we have in an article upon that genus noticed,) 

 for the most complete account hitherto published of 

 this curious group of parasites, and which were ob- 

 served by him in his voyage to the whale fisheries in 

 the Southern Ocean. Previous to the publication of 

 his memoir in the Annales des Sciences Naturelles 

 for May 1834, one species only had been described, 

 although Latreille in the Regne Animal had men- 

 tioned the existence of two other species inhabiting 

 the Indian seas and the ocean near the Cape of Good 

 Hope. M. Roussel, however, not only distinctly de- 

 scribed three species living upon the whales of the 

 Southern Ocean, but also observed their respective 

 habits. 



Sometimes these creatures are so abundant upon 

 the whales, that the infested animals can be easily 

 recognised at a very considerable distance by the 

 white colour which they impart to the whale, and 

 which is visible when it rises to the surface. When 

 these parasites are removed the surface of the body is 

 found to be deprived of the epidermis, and as it were 

 corroded. They are ovoviviparous, producing eggs 

 which are received into and hatched within the pouch- 

 iike plates on the undersides of the centre of the 

 body, at times eggs alone, at others both eggs and 

 young, and at others young only being observable in 



NAT. HIST. VOL. II. 



the pouch. Cyamus ovalis and gracilis are stationary, 

 being found in great numbers agglomerated upon the 

 corneous eminences of the SaUena mysticetus. C. 

 erraticus is, however, organised for its wandering 

 habits, being of a slender form and with stronger legs 

 serving for prehension. The young ones appear 

 with all the characters of their kind, only the head is 

 rather large, and the supposed branchial appendages 

 instead of being long and slender are short and some- 

 what globose ; the females of C. ovalis cover their 

 young with their bodies, whilst those of C. eiraticus 

 abandon their young conformably to their own mode 

 of life ; and in C. gracilis the females, males, and 

 young are all found mingled together. 



CYANELLA (Linnaeus). A bulbous genus from 

 the Cape of Good Hope. Linnaean class and order : 

 Hexandria Monogynia, and natural order Asphodelcee. 

 Generic character : corolla of six-spreading unequal 

 petals, inner ones longest : stamens below the ger- 

 men ; filaments united on a fleshy cup at the base ; 

 anthers erect, five are equal, bursting at vertical 

 pores ; the sixth twice the size, and oblong. Style 

 declining ; capsule three-celled, three-valved, and 

 many seeded. The flowers of this genus are of 

 various colours, handsome and sweet-scented. The 

 plants are kept in a pit or frame, or may be planted 

 in front of a hothouse, where they will succeed if 

 defended from frost. 



CYANITE, a mineral which derives its name 

 from a Greek word, indicative of its sky-blue colour. 

 When pure, it is idio-electric, as some crystals by 

 rubbing acquire negative electricity, and others with 

 a similar surface positive electricity : hence the name 

 disthene, given by Hauy to this mineral on account 

 of its double electrical powers. It occurs massive, 

 and disseminated ; and is sometimes regularly crys- 

 tallised. The primitive figure is an oblique, four-sided 

 prism. It is found in various parts of Europe, Asia, 

 and America. The Shetland Islands produce some 

 very beautiful specimens, and it is readily distin 

 guished from actynolite by its cleavage and infusi- 

 bility. 



CYANUS. Is the Centaurea cyanus of botanists 

 a common plant in corn-fields, provincially called 

 blue-bottle. 



CYATHEA (Smith). A West-India fern, of tree- 

 like stature, and highly ornamental. It was described 

 as a SpJuBroptcris by Bernhardi and Wallich, and 

 Peranema by Don. 



C YBI (JM, a genus of spinous-finned fishes, belong- 

 ing to the mackarel family, SCOMBKROID^E, which see. 



CYC ADE^, the Cycas family. A natural order 

 of dicotyledonous monochlamydeous plants, contain- 

 ing two genera, and nearly thirty known species. 

 Much difference of opinion has existed among bota- 

 nists as to the particular situation which this order 

 ought to occupy in the natural system. By some it 

 has been included in the monocotyledonous or endo- 

 genous class of vegetables. In so doing these authors 

 have laboured under an obvious misapprehension as 

 to the real structure of the cycadeae. The order may 

 be said to have a nearly equal relation to the flower- 

 ing or flowerless plants ; agreeing with the former in 

 the presence of the sexes and the completeness of 

 the vascular tissue, and with some of the latter, such 

 as ferns, in the peculiar gyrate vernatim of the leaves, 

 and the imperfection of the spiral vessels. By Lind- 

 ley, Cycadcce are included along with Con/feres under a 

 section of vascular plants, to which he has applied 



