Auricles sentence example
Heart with two auricles; ventricle traversed by the rectum, except in the Helicinidae.
Immediately before arrest the heart may beat much faster than normally, though with extreme irregularity, and in the lower animals the auricles may be observed occasionally to miss a beat, as in poisoning by veratrine and colchicum.
Most free rotifers swim by the corona, aided by the ciliated auricles when present.
Illoricata, cuticle soft; ciliated exsertile auricles above the disk sometimes present.
A dorsal contractile heart, with symmetrical right and left auricles receiving aerated blood from the ctenidia and mantle skirt, is present, being unequally developed only in those few forms which are inequivalve.Advertisement
Hence it passes through the vessels of the glandular walls of the nephridia right and left into the gilllamellae, whence it returns through many openings into the widelystretched auricles.
Previously to Hoek's discovery a brown-coloured investment of the auricles of the heart of the oyster had been supposed to represent the nephridia in a rudimentary state.
In addition to the characters given above, it may be noted that the mantle is provided with a hypobranchial gland on the outer side of each gill, the auricles are muscular, the kidneys are glandular through their whole length, the sexes are separate.
In Nautilus two pairs of auricles are present, corresponding with the two pairs of ctenidia.
Some blood, however, enters the auricles directly from the mantle, without passing through the ctenidia.Advertisement
The heart is enclosed in the pericardium, and consists of a median elongated ventricle and a pair of lateral auricles, so that the structure somewhat resembles that in the Lamellibranchiata.
The openings of the auricles into the ventricle vary in different forms. In many of the lower forms (Lepidopleuridae, Mopalidae, Ischnochitonidae) the opening on each side is single and anterior.
In the true Chitonidae there are generally two apertures on each side, and in two species three or four, another instance of the tendency to metameric repetition in the group. The auricles are connected with one another posteriorly behind the ventricle.
They may occur Au, Auricles.
The frequency of an opening between the right and left auricles at the seat of the fetal foramen ovale.Advertisement
As additional features of the subclass may be mentioned the absence of a corpus callosum connecting the right and left hemispheres of the brain,' and of a fossa in the septum between the two auricles of the heart.