Pritchard's last edition is against necks, and whether the necks or no necks are to win, is a mighty question equal at least to the famous controversy, which divided the world into "big and little endians in the matter of breaking eggs."
A discussion of more importance is, whether these Cryptomonads—that name will do whatever comes of the neck controversy—are animals or vegetables. Lachmann and Mr. Carter affirm that they have detected a contractile vesicle, which would assimulate them to the animal series, but their general behaviour is vegetable; and the 'Micrographic Dictionary' is in favour of referring them to the Algæ—that great family of simple plants, of which the sea-weeds are the most important representatives.
Triarthra.
When any of the monads swarm, there are sure to be plenty of other creatures to eat them up, and in this instance the predaceous animalcule, already described, was not the only enemy the little green globes had to suffer from, as two sorts of rotifer were frequently met with. One of these was a very handsome and singular creature, which in some positions had the general contour of a cockatoo, only that the legs were wanting, and the head exhibited a monkey face. The "wheels" were represented by ciliary tufts, and two bright red eyes twinkled with a knowing look. From each shoulder proceeded a long curved spine, and about two thirds down the body, and lying between the two long spines, a shorter one was articulated, which followed the same curve. A gizzard was busy in the breast, and the body terminated in two short toes, which grasped a large round egg. Whenever the cilia were drawn in, the three spines were thrown up; but they had an independent motion of their own, and every now and then were jerked suddenly and violently back, which occasioned a rapid change in the creature's position. The gizzard appeared to consist of two rounded masses, having several ridges of teeth, which worked against each other something like the prominences of a coffee-mill. From the three spines, this animal was a Triarthra, or Three-limbed Rotifer, but the position of the spines, and the toes, made it differ from any species described in the 'Micrographic Dictionary,' or in Pritchard.
Whether or not this species is to be regarded as having a lorica or not, must depend upon the precise meaning attached to that word. At any rate the integument was much firmer than in many of the rotifers, and gave an efficient support to the spines which a mere skin could not do. As Mr. Gosse remarks of an allied genus, the Polyarthra, or Many-limbed Rotifer, this creature could not be investigated without coming to the conclusion "Here again we have true jointed limbs;" a fact of great importance in determining the zoological rank of the family, and in supporting Mr. Gosse's view some at least bore a strong affinity with the group of Arthropoda, of which the insects are the principal representatives.
Brachionus urceolaris. This drawing has been accidentally reversed by the engraver, which alters the relative place of the internal organs.
Another rotifer of even greater interest, which was busy among the Cryptomonads, was the Brachion, or "Pitcher Rotifer" (Brachionus). The members of this genus will frequently reward the searcher into pond-life. Their main characteristic is a cup or pitcher-shaped lorica, which is cut or notched at the top into several horns or projections, the number of which indicates the species; while two or more similar projections ornament the bottom. This lorica is like the shell of a tortoise open at both ends; from the top an extremely beautiful wreath of cilia is protruded, and also some longer and stiff cilia, or slender spines, which do not exhibit the rotatory movement. The ciliary apparatus is in reality continuous, but it more often presents the appearance of several divisions, and the lateral cilia frequently hang over the sides. From the large size of each cilium they are very favorable creatures for exhibiting the real nature of the action, which gives rise to the rotatory appearance, and which can be easier studied than described. By movements, partly from their base, and partly arising from the flexibility of their structure, the cilia come alternately in and out of view, and when set in a circular pattern, the effect is amazingly like the spinning round of a wheel. The internal arrangements of the Brachiones are finely displayed, and they have a most aldermanic allowance of gizzard, which extends more than half way across each side of the median line, and shows all the portions described by Mr. Gosse. As the joints of this machine move, and the teeth are brought together, one could fancy a sound of mill-work was heard, and the observer is fully impressed with a sense of mechanical power.
When the creature is obliging enough to present a full front view, her domestic economy is excellently displayed. The prey that is caught in her whirlpool is carried down by a strong ciliary current to the gizzard, which may be often seen grappling with objects that appear much too big for its grasp; and Mr. Gosse was lucky in witnessing an attempt to chew up a morsel that did actually prove too large and too tough, and which, after many ineffectual efforts, was suddenly cast out. As soon as food has passed the gizzard, it is assisted in its journey by more ciliary currents, which are noticeable in the capacious stomach, in the neighbourhood of which the secreting and other vessels are readily observed. Just over the gizzard blazes a great red eye, of a square or oblong form, and it reposes upon a large mass of soft granular-looking brain, which well justifies Mr. Gosse's epithet "enormous." Whether this brain is highly organized enough to be a thinking apparatus, we do not know, but it is evidently the cause of a very vigorous and consentaneous action of the various organs the Brachion possesses.