. Anatomischer Anzeiger. Anatomy, Comparative; Anatomy, Comparative. 278 A n D u 1 a t a. Arenicola cristata. Each ovary in this species is situated on the wall of a blood vessel which extends along the nephridiuui. The animals produce an enormous number of eggs throughout most of the summer. Passage of the eggs to the exterior occurs more than once—probably several times— during the season. Ovaries of this species sectioned during early summer and when the coelom contained eggs of all sizes from those just set free from the ovary to those fully grown show very large numbers of primitive oogon
. Anatomischer Anzeiger. Anatomy, Comparative; Anatomy, Comparative. 278 A n D u 1 a t a. Arenicola cristata. Each ovary in this species is situated on the wall of a blood vessel which extends along the nephridiuui. The animals produce an enormous number of eggs throughout most of the summer. Passage of the eggs to the exterior occurs more than once—probably several times— during the season. Ovaries of this species sectioned during early summer and when the coelom contained eggs of all sizes from those just set free from the ovary to those fully grown show very large numbers of primitive oogonia and every indi- cation of rapid production of new cells. As yet, however, I have not been able to find a single case of mitosis in these sections. My ob- servations here are not very extensive and it may be that mitosis does occur. Synapsis stages are frequently seen and may readily be mistaken by the casual observer for early stages of mitosis, but numerous cases of what appears very clearly to be amitosis are present in all sections which include stages before synapsis. In Figure 4, I—V, a number of. Fig. 4. cases all taken from a single sections'are shown. This same section contained many more equally convincing cases. These phenomena are exceptionally distinct and clear in this form and error seems impos- sible. In connection with my other work along this line it occurred to me recently that the so-called cessation of cleavage in various embryos and larval forms might be at least in some cases a change from niitotic to amitotic division. Unfortunately I have not been able as yet to obtain any large series of preparations for testing this point. Having. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Anatomische Gesellschaft. Jena : G. Fischer
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