In the living forms, and probably in all others, a matter which can never be ascertained, the optic nerves are not decussating, but form an optic chiasma, and the intestine is provided with a spiral valve.
The presence of a spiral valve; though this character may possibly break down with the extension of our knowledge.
The intestine is often provided with a spiral valve, like Elasmobranchii.
In all forms in which there is not a spiral valve, with the exception of a few Teleostei, the intestine becomes considerably longer than the cavity which contains it, and therefore necessarily more or less convoluted.
In the sharks or skates the rectum or large intestine is peculiarly modified, being provided with a spiral valve, with sometimes as many as forty gyrations.
Among these are the mailed head and body, the heterocercal tail, the cellular air-bladder, the presence of valves in the arterial bulb, the presence of a spiral valve in the intestine and of a chiasma in the optic nerves.
A spiral valve is also present in the more ancient types of the true fishes as dipnoans, crossopterygians, and ganoids.
In some forms, as the pig, the left extremity of the stomach carries a caecal appendix with a spiral valve in the interior separating its lumen from the general gastric cavity (Fig.
The middle segment of the intestine, presenting a spiral valve in the interior, gives rise to a vein emptying into the portal vein which corresponds to the subintestinal vitelline vein of the mammalian embryo (Fig.
In Elasmobranchii the lumen of the part of the intestine in which a spiral valve is present in the adult, very early acquires a more or less semilunar form by the appearance of a fold which winds in a long spiral.
The above list will hopefully provide you with a few useful examples demonstrating the appropriate usage of "spiral valve" in a variety of sentences. We hope that you will now be able to make sentences using this group of words.
