The Stentors obey the injunction to "increase and multiply" by self-division, which Stein says is always oblique, and the nucleus, which plays such an important part in infusoria, is band-like, moniliform (bead-shape), or round. When an animalcule increases by self-division, a portion of the nucleus goes with each part, and it is probably the organ which stimulates the change. It is also concerned in other modes of propagation. "The anus is situated on the back close beneath the ciliary circle;" and the "contractile vesicle on a level with the ciliary wreath." Stein records that in November, 1858, he met green Stentors (Polymorphus) encysted, and he figures one in a gelatinous flask having a stopper in its narrow neck.
Before closing our account of the Stentor, let us revert a moment to the ciliary wreath, as it may be made the subject of a curious experiment. If, for example, the cilia are viewed at right-angles to their length, they will seem to form a delicate frill, in which a quivering motion is perceived. But if the table is shaken by a sharp blow, the frill is thrown into waves, or takes the form which washerwomen give to certain female articles by the use of the Italian iron, and the ciliary motion is thus made to take place in different planes, and rendered strikingly apparent.
One day turning over the Anacharis in search of subjects, a small brown tube was noticed, from which a glassy rod protruded like the feeler of a rotifer. Keeping the table quiet, and watching the result, was soon rewarded by a further protrusion of the feeler, accompanied by a portion of the body of the inmate of the tube. The feeler was thrust on this side and on that, as if collecting information for its proprietor, who, I suppose, was satisfied with the intelligence, and gradually extended herself, until she stood out two thirds in length beyond the tube, and set two lobes of one nearly continuous ciliary organ in rapid motion. Sometimes the creature, Cephalosiphon limnias, bent its neck, if I may so speak, to the right, and sometimes to the left, and sometimes stood upright, when the true form of the ciliary apparatus could be seen. The tube of this creature was opaque, from the adhesion of foreign matter, and presented an untidy appearance, strangely contrasting with the clear, neat bottles of the Floscules. These Cephalosiphons are very whimsical in their ways, and many that were sent to different observers never exhibited their ciliary wreaths, but performed sundry antics, disguising their true shape.
Cephalosiphon limnias.
Somewhat like the Cephalosiphon, though much commoner and without the siphon, is Limnias ceratophylli, which every collector is sure to meet. The length of the Limnias varies, according to Pritchard, from 1—20" to 1—40". Our Cephalosiphon, when fully extended and magnified one hundred and eighty linear, looked about three inches and a half long, and was therefore very small. Just below the ciliary lobes the gizzard was seen, with its toothed hammers working one against the other. The masticatory organ differs from the typical form, as represented in the Brachion; and Mr. Gosse observes of Limnias that "each uncus forms, with its ramus, a well-defined mass of muscle enclosing the solid parts, and in form approaching the quadrature of a globe. Across the upper surface of the mass the uncus is stretched like three long parallel fingers, arched in their common direction, and imbedded in the muscular substances, their points just reaching the opposing face of the ramus, and meeting the points of the opposite uncus when closed."[20]
[20] The terms uncus, ramus, etc., have been explained in Chapter II, page 28.
There is no connection between Limnias or Cephalosiphon and their tubes, except that of simple adhesion, which takes place by means of the end of their foot-stalks.
In a former chapter we have described an interesting relation of the Vorticella, the Cothurnia, whose elegant crystal vases form a very artistic abode, characterised by possessing a distinct foot. Other species of the same family inhabit vases which have no foot or stalk, or live in gelatinous sheaths less accurately fashioned. Sometimes these creatures are obliging enough to conform to the specific descriptions which eminent naturalists have given of them, and also to the characters which the authorities have assigned to the different genera in which they have been grouped, but the microscopist will often meet with difficulties in the way of classification.
