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Show 48 IIADITS OF ·woRMS. CHAP. I. larger free cells were seen on three occasions; and these contained a distinct nucleus and nucleolus. They were only so far acted on by acetic acid that the nucleus was thus rendered more distinct. .A.. very small concretion was removed from between two of the lamellre within an anterior gland. It was embedded in pulpy cellular matter, with many free calciferous cells, together with a multitude of the larger, free, nucleated cell , and these latter cells were not acted on by acetic acid, while the former were di ssolved. From this and other such cases I am led to suspect that the calciferous cells are developed from the larger nucleated ones; but how this is effected was not ascertained. When an anterior gland contains several minute concretions, some of these are generally angular or crystalline in outline, wl1ilo the oTeater number are rounded with an irrcp;no lar mulberry-like surface. Ca1ci ferou. cells adhered to many parts of the e mulberry-like masses, and their gradual di~appearance could be traced while they still remained attached. It was thus evident that tho concretion arc formed frmn the lime . contained within the Orr.AP. I. CALCIFEROUS GLANDS. 49 free calciferous cells. As the smaller concretions increase in size, they come into contact and unite, thus enclosing the now functionless lamellre; and by such steps the formation of the largest concretions could be followed. Why the process regularly takes place in the two anterior glands, and only rarely in tho four posterior glands, is quito unknown. Mo~ren says that these glands disappear dunng the winter ; and I have seen some instances of this fact, and others in which either_ the anterior or posterior glands were at this season so shrunk and empty, that they could be distinguished only with much difficulty. With respect to the function of the calcifero~ s glands, it is probable that they primanly serve as organs of excretion, and secondarily as an aid to digestion. Worms consume many fallen leaves; and it is known that lime goes on accumulating in leaves until th~y drop off the parent-plant, instead of bei~g re-absorbed into the stem or roots, like varwus other organic and inorganic substances.* The ashes of a leaf of an acacia * De Vries, 'Lan<.lwirth. Jahrbtichor,' 1881, p. 77. E |
