Together with currents of water induced by the action of the vibratile cilia which are abundant along special tracts on the sides and roof of the vestibule of the mouth and in the walls of the perforated pharynx ("ciliary ingestion").
Pelagica) there is an outer girdle of fine cilia for swimming.
Neither here nor elsewhere are cilia found at any period of development.
The epidermis has lost its connected epithelial character and its cilia, and the isolated cells have become sunk inwards retaining their S t- FIG.
From each locule of a plurilocular sporangium there is set free an oosphere, which, being furnished with a pair of cilia, swarms for a time.
Bonaini's Statuti inediti della cilia di Pisa (3 vols., Florence, 1851, &c.).
Some, however, are wanderers, either swimming actively with the aid of cilia, or floating inertly as the result of a specific weight closely approaching that of the medium.
The cytoplasm is largely concerned in the formation of spindle fibres and centrosomes, and such structures as the cell membrane, cilia, or flagella, the coenocentrum, nematoplasl~ or vibrioids and physodes are also products of its activity.
By the aid of these cilia the larva swims actively, but owing to its minute size it covers very little distance, and this probably accounts for the fact that where brachiopods occur there are, as a rule, a good many in one spot.
The cilia are lost, the eye-spots disappear, the digestive sac vanishes and the larva becomes a sac or "sporocyst" full of germ-cells.
For the Bonaparte family in general, and Carlo and Letizia, see Storia genealogica della famiglia Bonaparte, della sua origine lino all' estinzione del ramo gia esisente nella cilia, di S.
In Nucula delphinodonta the test is uniformly covered with short cilia, and there is no flagellum.
A certain inequality in the character of the two cilia of the zoospores of some of the members of the group has earned for it the title Heterokontae, from the Greek xovros, a punting-pole.
The zoospore is usually a pyriform mass of naked protoplasm, the beaked end of which where the cilia arise is devoid of colouring matter.
The movement of the zoospore is effected by the lashing of the cilia and is in the direction of the beak, while the zoospore slowly rotates on its long axis at the same time.
If successful, the larva throws off its cilia and develops a dorsal papilla, a median ventral sucker and an additional pair of lateral suckers.
The microscope shows that the neighbouring filaments are held together by patches of cilia, called " ciliated junctions," which interlock with one another just as two brushes may be made to do.
Shown by the two projecting en, Invaginatedendoderm(wallof cilia on the upper part of the the future arch-enteron).
The branchial current is maintained by the cilia which cover the surface of the ctenidia, except in Cephalopoda, in which cilia are absent and the current is due to muscular action.
Usually two cilia are present; in Botrydium and Hydrodictyon only one is present; in certain species of Cladophora four; in Dasycladus a chaplet, and in Oedogonium a ring of many cilia.
In some cases both the nucleus and the chromatophores may be carried along in the rotating stream, but in others, such as T.Titeila, the chloroplasts may remain motionless iii a non-motile layer of the cytoplasm in direct contact with the cell wall.i Desmids, Diatoms and Oscillaria show creeping movements probably due to the secretion of slime by the cells; the swarmspores and plasmodium of the Myxomycetes exhibit amoehoid movements; and the motile spores of Fungi and Algae, the spermatozoids of mosses, ferns, &c., move by means of delicate prolongations, cilia or flagella cf the protoplast.
In the spermatozoids of Chara, Vascular Cryptogams, and in those of Cycas, Zamia and Ginkgo, the cilia arise from a centrosome-like body which is found on one side of the nucleus of the spermatozoid mother-cell.
This body has been called a blepharoplast, and in the Pteridophytes, Cycads and Ginkgo it gives rise to the spiral band on which the cilia are formed.
Even in those cases where the cilia band, which is the product of the centrosome-like body or blepharoplast, enters the ovum, as in Zamia (c in fig.
Rarely the nephridium does not communicate with the coelom; in such cases the nephridium ends in a single cell, like the "flame cell" of a Platyhelminth worm, in which there is a lumen blocked at the coelomic end by a tuft of fine cilia projecting into the lumen.
The chief modifications of this form are seen in the Mitraria larva of Ammochares with only the preoral band, which is much folded and which has provisional and long setae; the a.trochous larva, where the covering of cilia is uniform and not split into bands; and the polytrochous larva where there are several bands surrounding the body.
The efferent ducts are ciliated, and there is a patch of cilia at the point where they communicate with the cavity of each testis.
Small tufts of tactile hairs or papillae are sometimes observed in small number at the tip of the head; sometimes longer hairs, apparently rather stiff, are seen on the surface, very sparingly distributed between the cilia, and hitherto only in a very limited number of small specimens.
See Casagrandi, Su due antiche cilia sicule Vessa ed Inessa (Acireale, 1892).
At the end of each twig is a membrane pierced by pores, and a number of cilia depend into the lumen of the tube; these cilia maintain a constant motion.
The water which bears the oxygen for respiration and the minute organisms upon which the Brachiopod feeds is swept into the mantle cavity by the action of the cilia which cover the arms, and the eggs and excreta pass out into the same cavity.
The so-called zoospore of Vaucheria is a coenocyte covered over with paired cilia corresponding in position to nuclei lying below.
It loses many of its larval organs, cilia, takes in a quantity of water into its body-cavity, sinks to the bottom of the sea, and begins life in its final form.
Polygordius and Protodrilus live in sand, but while the former moves by means of the contraction of its body-wall muscles, Protodrilus can progress by the action of the bands of cilia surrounding its segments, and of the longitudinal ciliated ventral groove.
It was formerly the custom to include with the Fungi the Schizomycetes or Bacteria, and the Myxomycetes or Mycetozoa; but the peculiar mode of growth and division, the cilia, spores and other peculiarities of the former, and the emission of naked amoeboid masses of protoplasm, which creep and fuse to streaming plasmodia, with special modes of nutrition and spore-formation of the latter, have led to their separation as groups of organisms independent of the true Fungi.
The peripheral paren chyma gives rise to protonephridia, that is to coiled tubes commencing in pyriform cells containing a flame-like bundle of cilia and provided with branched outgrowths, and communicating with the exterior by long convoluted canals which open at the surface of the body.
(iv.) Trophi uncinate: Flosculariaceae; disk a contractile cup, often lobed, the cingulum of long vibratile cilia, of very long motionless bristles or absent, rarely with an outer zone of fine cilia.
Now familiarly known as "wheel 'animalcules," from the wheel-like motion produced by the rings of cilia which generally occur in the head region, the so-called rotatory organs, they were first discovered by A.
In most rotifers, on the contrary, the trochus is stronger than the cingulum, often lobed, and with some of its cilia aggregated into vibratile styles homologous with the combplates of Ctenophora (q.v.) and the membranelles of ciliate Infusoria (q.v.).
The current formed by the trochus is a gigantic vortex-ring, the down stroke of the cilia being directly outwards, brit the wave beats running round the organ in uniform succession in one direc tion.
The larva for a time swims freely in the sea-water, having a circlet of cilia round the body in front of the mouth, forming the velum.
In the development of the Hydrozoa, and indeed of the Cnidaria generally, the egg usually gives rise to an oval larva which swims about by means of a coating of cilia on the surface of the body.