Crossword clues for furcula
The Collaborative International Dictionary
Furcula \Fur"cu*la\, n. [L., a forked prop, dim. of furca a fork.] (Anat.) A forked process; the wishbone or furculum.
Wiktionary
n. 1 (context anatomy English) A forked process or structure, generally two-pronged. 2 (context ornithology English) The forked bone formed by the fusion of the clavicles in birds, the wishbone or merrythought. 3 (context entomology English) The (two-pronged) forked, somewhat tail-like organ held bent forward and secured by a catch beneath most species of Collembola (springtails), with which they jump by releasing the catch abruptly when alarmed.
WordNet
n. a forked bone formed by the fusion of the clavicles of most birds
[also: furculae (pl)]
Wikipedia
The furcula, or furca is present in most species of springtails. It is a forked, tail-like appendage, attached ventrally to the fourth abdominal segment. The organ most often is present in species of Collembola that live in the upper soil layers; they use it for jumping when the animal is threatened. While at rest, it is retracted under the abdomen and held there by a structure variously called the retinaculum or hamula, which in turn is located beneath the third abdominal segment. When the furcula escapes from retinaculum, it swings downwards and hits the substrate, propelling the springtail into the air. The animal does not use this mechanism for locomotion, but only for escaping from predators or severe stress.
One reason not to use the furcula for general locomotion other than to escape threats, is that its action is very unpredictable; when the furcula is released, the springtail is sent tumbling through the air on a practically arbitrary trajectory, and lands almost randomly. That may have advantages in escaping some forms of attack, but is not of much use in adopting any particular route.
Although the action of the furcula is hard to predict, it is versatile. Even a springtail drifting on the surface tension of a layer of water often can jump successfully. Furthermore the furcula is effective in environments typical of Collembola; most predators of springtails are small and many have little power of sight, so if the prey leaps in time, the chances are that from the hunter's point of view, it simply vanishes.
Some species of Collembola, for instance in the genus Hypogastrura, have only a very short furcula. Some other species have no furcula at all; examples include the intertidal marine species Anurida maritima and some riparian species that live on the brink of flowing fresh water. The absence of a furcula in such species commonly is explained as an adaptation to a way of life in which a jumping or flying organ might get the animals into trouble more often than it rescues them. Its loss presumably is analogous the loss of the ability to fly, such as is common among birds and insects inhabiting oceanic islands.
Usage examples of "furcula".
Photodilus seem not to have been investigated, but it has been found to want the tarsal loop, as well as the manubrial process, while its clavicles are not joined in a furcula, nor do they meet the keel, and the posterior margin of the sternum has processes and fissures like the tawny section.
For to omit the hioides or throat-bone of animals, the furcula or merry-thought in birds, which supporteth the scapulæ, affording a passage for the winde-pipe and the gullet, the wings of Flyes, and disposure of their legges in their first formation from maggots, and the position of their horns, wings and legges, in their Aurelian cases and swadling clouts: The back of the Cimex Arboreus, found often upon Trees and lesser plants, doth elegantly discover the Burgundian decussation.
In the frigate-bird the symphysis of the furcula coalesces with the carina and the upper end of each ramus with the caracoid, while in its turn each caracoid coalesces with the proximal end of the scapula!