Page:The aquarium - an unveiling of the wonders of the deep sea.djvu/281

226 them. The scalloped Cockles of Paignton we had known only by reputation; we tried them in this way, and found them worthy of their fame.

Mr. Kingsley has favoured me with the following observations on the respiration of these species. "Whether Mr. Clark be right or not in saying that the water is received through both siphons, he is right against Mr. Alder and Mr. Cocks, in saying that it is expelled through both. What I see is this. From the small anal siphon, the water is expelled in steady periodic currents, forming a ripple (under three inches of water) several inches off. From the large siphon it is expelled seldom and capriciously, in a violent jet; give ten a minute to the small, one in four or five minutes to the large. If disturbed they commonly jet the water from the large tube.

"The large siphon opens periodically,—I think answering to the jets of the small siphon,—till it is quite circular. The small one almost always keeps an oval form: I can see no inward current in either. Clark is right in saying that they lie long without using the siphons; sometimes they are not out for a whole day.

"What is the use of the fringes? They cannot strain the water in so large an animal as this Cockle, which, when the siphon is open, has a $$\tfrac{1}{3}$$ inch pipe fully patulous."

When once we have begun to look with curiosity on the strange things that ordinary people pass over without notice, our wonder is continually excited by the