Studies from the Biological Laboratory

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated.1879 Excerpt: ... THE DEVELOPMENT OP AMBLYSTOMA PUNCTATUM, Baird. Part I, External. By SAMUEL F. CLARKE, Ph.d., Balt., Assistant in the Riologiral Laboratory and sometime Fellow of the Johns Hopkins University. In early March of 1878, I obtained in early stages of development a number of eggs which I believed to b those of some Urodele. They were found in considerable numbers in the pools and small streams in and near the woods about Baltimore, during the months of March and April. They occurred in gelatinous masses, Plate 4, Figure 30, which varied greatly in size, were usually more or less oval in shape, and attached to the stem of some aquatic plant or to an overhanging blade of grass. This year I was so fortunate as to secure living specimens of both sexes of Amblystoma punctatum before the females had deposited their eggs. They all did well in confinement; the males furnished an abundance of spermatozoa at the critical moments, the eggs passed through their various phases of development, and a record of the external change is preserved by a series of cameralucida drawings. The animals derived from the eggs brought to me in the spring of 1878, were studied with considerable care and received considerable attention in respect to their food and surrounding conditions. I was unable, however, to keep them after they reached the abranchiate stage, and in consequence could not determine what form I had been at work upon. I was much pleased then to find upon carefully comparing the eggs laid by the adults in my aquaria this spring, their course of development and their more advanced forms, that they agree in every particular with the eggs and young forms which had occupied my attention in the previous years. By getting the ege;s in this way I was able also to obtain the c...