Flagellum

“ DINOFLAGELLATA, so called by O. Bütschli (= the Cilioflagellata of E. Claparide and H. Lachmann) , a group of Protozoa, characterized as Mastigophora, provided with two flagella, the one anterior extended in locomotion, the other coiled round its base, or lying in a transverse groove. The body is bounded by a firm pellicle, often supplemented by an armour (“lorica”) of cuticular cellulose plates, with usually a marked longitudinal groove from which the anterior flagellum springs, and an oblique or spiral transverse groove for the second flagellum. ”

“ An anterior lateral trailing flagellum may modify this axial rotation, and help in steering. When the animal is at rest—attached by its base or with its body so curved as to resist onward motion—the current produced by the tractellum will bring suspended particles up against the protoplasm at its base of insertion. As noted by E. R. Lankester, the posterior flagellum of many Haemoflagellates, like that of the spermatozoon of Metazoa, propels the cell by a sculling motion behind ”

“ Adjoining or surrounding the blepharoplast is a small non-staining area, the vacuole. The free border of the undulating membrane is somewhat thickened; this thickened border springs from the blepharoplast at one end, and its continuation at the other constitutes the flagellum. In certain specimens the cytoplasm is homogeneous; in other specimens comparatively faintly staining granules are visible. In comparing and measuring a large series of specimens, it becomes apparent that there is great diversity in the dimensions of the body of the parasite, the nucleus, and the flagellum (Fig. 46) . ”

“ As will be seen in Fig. 31, each of the endoderm cells of the tentacles has a flagellum that extends into the lumen of the tentacle. Each flagellum has a thickening just within its cell, which may be regarded as a basal body. From this basal body, again, a small fiber extends centrad into each cell. It does not appear that the flagella are thrown off with the distal parts of the cells ”

“ The newly-fissioned form darted irregularly and rapidly for a brief space, then fixed itself to the floor or to a rigid object by the ends of its flagella, and, with its body motionless, an intense vibratory action was set up along the entire length of these exquisite fibers. Rapidly the ends split, one-half being in each fiber set free, and the other remaining fixed, and in 130 seconds each entire flagellum was divided into a perfect pair. ”

“ In this condition, it need hardly be remarked that the spherical form is common and general among a great variety of unicellular organisms. When our little monad developes a flagellum, that is in itself an indication of “polarity” or symmetrical non-homogeneity of the cell; and accordingly, we {247} usually see signs of an unequal tension of the membrane in the neighbourhood of the base of the flagellum. Here the tension is usually less than elsewhere, and the radius of curvature is accordingly less: in other words that end of the cell is drawn out to a tapering point (Fig. 73) . ”

“ It is a plausible assumption to suppose that, as the flagellum waves about, it comes to lie near and parallel to the body of the cell, and that the frill or undulating membrane is formed by the clear, fluid protoplasm of the surface layer springing up in a film to run up and along the flagellum, just as a soap-film would be formed in similar circumstances. ”

“ Order 5.—EUGLENACEAE. Vacuole large, a reservoir for one or more accessory vacuoles, contractile and opening to the surface by a canal (“pharynx”) in which are planted one or two strong flagella; pellicle strong often striated; nucleus large, chromatophores green, complex or absent; reserves paramylum granules of definite shape, and oil; nutrition variable; body stiff or “metabolic,” never amoeboid. Among the true Flagellates these are the largest, few being below 40 μ and several attaining 130 μ in length of cell-body (excluding flagellum) . ”

“ Bütschli’s theory of Protozoan phylogeny implies that a flagellum is an organ of most primitive nature, possessed perhaps by the earliest forms of life; and it must be remembered that flagella are borne by many Bacteria. On the other hand, one would imagine, from general considerations, that living beings possessing a flagellum would have been preceded in evolution by others that did not bear so definite an organ. ”

“ Herpetomonas is a generic name for certain flagellates possessing a vermiform or snake-like body, a nucleus placed approximately centrally, and a blepharoplast (kinetic nucleus) near the flagellar end. There is no undulating membrane (fig. 49, a) . The organisms included in this genus certainly possess one flagellum, while according to Prowazek (1904) Herpetomonas muscæ-domesticæ, the type species, possesses two flagella united by a membrane. ”

“ It is quite a common thing to find nearly all the adult flagellates in a fly exhibiting this appearance of a double flagellum. If the mid-guts of a number of flies are next examined in the fresh condition, in some, the flagellates will be seen collecting together towards the rectum, they attach themselves in rows by their flagellar ends to the gut-wall, and now further changes are seen to occur. ”

“ It was greatly advanced by the method of double staining (with alkaline methylene blue and eosin) introduced by Romanowsky (1891) and elaborated by Ziemann, Leishman, Giemsa and others. By this means the presence of a terminal flagellum and of an undulating membrane at the side of the flattened and extended body was demonstrated. Laveran and Mesnil (1901) discovered allied flagellates in the blood of the fish, Scardinius erythrophthalmus. These flagellates, now placed in the genus Trypanoplasma, had a second free flagellum in addition to the one bordering the undulating membrane. ”

“ The genus Trichoniscus has four joints in the flagellum; various species are found in woods. In Porcellio and Armadillidium there are only two joints in the flagellum, while Armadillidium, the common garden wood-louse, can be distinguished from all others by the flattened shape of the uropods, and the habit of rolling up into a ball like an Armadillo. ”

“ Others were made of a number of cords of twisted parchment, and were called Scuticæ. These Scuticæ were considered as being a degree higher in point of severity than the ferulæ, but were much inferior, in that respect, to that kind of scourge which was called Flagellum, and sometimes the terrible Flagellum, which was made of thongs of ox-leather, the same as those which Carmen used for their Horses. We find in the third Satyr of the first Book of Horace, a clear and pretty singular account of the gradation in point of severity that obtained between the above-mentioned instruments of whipping. ”

“ The second is the proton conductor stator that provides the rotary force, which is clearly related to the TonB/ExbB complex that in many negibacteria couples cytoplasmic membrane protein motive force to import across the OM. I suggest that the first flagellum originated by the novel combination of a slime-secretion nozzle and a modified TonB complex that became coupled to it, thus causing it to rotate. Later the tip of the nozzle evolved into the hook and shaft of the flagellum. ”

“ CYSTOFLAGELLATA (so named by E. Haeckel) , a group of Mastigophorous Protozoa, distinguished from Flagellata by their large size (0.15-1.5 mm.) , and their branched endoplasm, recalling that of Trachelius among Infusoria, within a firm ectosarc bounded by a strong cuticle. Nutrition is holozoic, a deep groove leading down to a mouth and pharynx. A long fine flagellum arises from the pharynx in Noctiluca (E. Suriray) Leptodiscus and (R. Hertwig) ; and in the former genus, a second flagellum, thick, long and transversely striated, rises farther out, in the groove ”

“ There is a small cytostome near the roots of the flagella. There is a well-marked karyosome in the nucleus. The movement is jerky. The shorter, anterior flagellum may be used in food-capture. In life, bacteria have been seen to be ingested. Food-vacuoles tend to accumulate at the posterior (aflagellar) end. A contractile vacuole may be present, near the base of the cytostome, and may really be the dilated fundus of the latter. Division occurs by binary fission. The organism can encyst (fig. 25, a) , when the flagella are lost, and round or oval cysts are found, 5 μ to 7 μ in diameter. ”

“ Antennæ capite transverso vix breviores; articulus 3us fusiformis; flagellum compressum, lanceolatum. Scutellum spinosum. Abdomen ellipticum, thorace latius non longius. Pedes breves, graciles. Alæ angustæ.
Female. Body somewhat elongated and depressed. Head somewhat oblong; eyes nearly contiguous in front, diverging hindward, where there is an elevated margin. Mouth and palpi very short. Antennæ nearly as long as the breadth of the head; 3rd joint fusiform, fully half the length of the flagellum, which is compressed and lanceolate, and with indistinct joints. ”

“ Some move about by the aid of a flagellum, or long whip-like projection of their bodies, by which they lash the surrounding waters, and which, unlike the pseudopodia of Amœba, can not, during active life, be withdrawn into the general protoplasm of the body; while among many others locomotion is effected by means of cilia—microscopic vibratile hairs, which are distributed in various ways over the surface, and which, like the pseudopodia and flagella, are simple prolongations of their protoplasm. ”

“ Female. Length 41⁄4 lines. Reddish yellow, smooth, and shining; the face testaceous, with slight fuscous stains; the scape and two or three of the basal joints of the flagellum yellow in front; the wings hyaline, with a yellowish tinge; the nervures black, except the costal nervure, which is ferruginous towards the base, the apex of the wings slightly clouded; the posterior tibiæ fuscous above. Abdomen: the segments with slightly impressed oblique depressions, the ovipositor shorter than the abdomen, and black.
The Male only differs in having the abdomen rather more slender. ”

“ Pouchetia (Schütt) (fig. 2, 7) with complex eye-spot; to this group we may refer Polykrikos (Bütschli) (fig. 2, 9) , with its metameric transverse grooves and flagella.
2. Prorocentraceae (Schütt) ( = the Adinida of Bergh) ; body surrounded by a firm shell of two valves without a girdle band; transverse groove absent; transverse flagellum coiled round base of longitudinal. Exuviaeella (Cienk.) (fig. 2, 3) ; Prorocentrum (Ehrb.) (fig. 2, 4) .
3. Peridiniaceae (Schütt) ; body with a shell of plates, a girdle band along the transverse groove, in which the transverse flagellum lies. ”

“ It produces rapid forward motion in a practically straight line, the head, middle piece, and forward portion of the tail maintaining their position in the line of motion with practically no swaying from side to side. The action of the flagellum is so rapid that it is quite impossible to follow its individual movements. Spermatozoa swimming in this manner head against the current and usually cross the field of observation in about five seconds in the absence of currents or obstacles. This type of motion will be described throughout the paper as ‘progressive vibratile’ motion. ”

“ In the first place we must consider the possibility that the secondary flagellum, which is not always easy to detect, may only have been overlooked by Savigny, as indeed Spence Bate supposes to have been the case. If it is really deficient it must be remarked that I have found it in species of the genera Leucothoë, Cyrtophium and Amphilochus, in which genera it was missed by Savigny, Dana and Spence Bate—that a species proved by the form of the Epimera (coxæ Sp. B.) of the caudal feet (uropoda Westw.) ”

“ Cell-wall firm not gelatinous, rarely forming colonies. Fore-end of the body with two or four (seldom five) flagella. Almost always green in consequence of the presence of a very large single chromatophore. Generally a delicate shell-like envelope of membranous consistence. 1 to 2 simple contractile vacuoles at the base of the flagella. Usually one eye-speck. Division of the protoplasm within the envelope may produce four, eight or more new individuals. ”

“ The Whip-swimmers (Flagellata) , which we consider as a third class of the kingdom Protista, are of no less doubtful nature than the Amœbæ. They often show as close and important relations to the vegetable as to the animal kingdom. Some Flagellata at an early stage, when freely moving about, cannot be distinguished from real plants, especially from the spores of many Algæ; whereas others are directly allied to real animals, namely, to the fringed Infusoria (Ciliata) . The Flagellata are simple cells which live in fresh or salt water, either singly or united in colonies. ”

“ When ingested by a new host, the post-flagellate coat becomes more flexible, and the phase of the organism which now recommences growth is known as the pre-flagellate stage; it gradually develops into the typical flagellate organism.
Many Flagellata live free in fresh and salt water. They prefer stagnant water, rich in organic products of decomposition, such as puddles, swamps and pools. Those forms developing shells and colonies are, as a rule, adherent. A number of species are parasitic in man and animals, living mostly within the intestine or in the blood. ”

“ As we were employed in making beds for the flax and placing it in them, we observed several nests of the flamingo. These are most curiously and skilfully made of glutinous clay, so strong that they can neither be overturned nor washed away. They are formed in the shape of blunted cones, and placed point downwards; at the upper and broader end is built a little platform to contain the eggs, on which the female bird sits, with her long legs in the water on either side, until the little birds are hatched and can take to the water. ”