. Zoölogy [microform] : descriptive and practical. Zoology; Zoologie. i * Ii8 Descriptive The Sense Organs. — The sense of touch is preeminent. This sense is best developed in the palps, along the margin of the mantle, especially that part of it which forms the borders of the siphons, and in the foot. There is no sense of sight, but the tentacles around the siphons seem somewhat sensitive to light. On a nerve near the pedal ganglion is the so-called "ear sac," of doubtful use. At the base of the gills is an organ sometimes called the "smelling patch," which, perha
. Zoölogy [microform] : descriptive and practical. Zoology; Zoologie. i * Ii8 Descriptive The Sense Organs. — The sense of touch is preeminent. This sense is best developed in the palps, along the margin of the mantle, especially that part of it which forms the borders of the siphons, and in the foot. There is no sense of sight, but the tentacles around the siphons seem somewhat sensitive to light. On a nerve near the pedal ganglion is the so-called "ear sac," of doubtful use. At the base of the gills is an organ sometimes called the "smelling patch," which, perhaps, has the office of testing the quality of the water. The sense of taste is doubtful, though it is probable that there is some discrimination as to what should be taken as food. The clam is sensitive to vibrations communicated either through the soil or the water. The Reproductive Organs. — Thc3e are diffuse glands enveloping the coils of the •'.'testine in the abdomen. The gl\nds in the two sexes (ovaries and spermaries) are so similar that it usually requires microscopic examination to distinguish them. The ducts, both in the male and female, open on the side of the body near the opening of the duct from the kidneys. The eggs, when mature, pass out of jhe duct and lodge in the gills (more often the outer gills) of the female. They are fertilized by the sperms, which have been set free in the water and are drawn in by the same current that brings the food particles. The males and females may sometimes be distinguished by the greater convexity of the shell in the female, the valves being more bulging to accommodate the accumulation of eggs and young clams in the outer gill. Development of the Clam. •— The young usually develop during the fall and winter. When liberated, the young clams are called Glochidia. They are of different shape from t' e adult, being ovate, with the hinge at the wider §|::%^^'^;^i^;-^^ WIWR '*.h^. Please note that these images are extracted
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1903
