. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 24 bulletin: museum of comparative zoology. According to my interpretation of the Vierergruppen in Calopte- nus, the formula would be i ^ ^ r • ^^th the divisions following the formation of a Vierergruppe would therefore be reductions, and it would be quite immaterial whether the first di- vision gave rise to two cells a h and c d, or to the two cells a c and h d. In Calop- tenus the rings may be placed upon the spindle equator in either of the two posi- tions represented in Diagrams 1 and 2. This offers, pei'haps, an
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 24 bulletin: museum of comparative zoology. According to my interpretation of the Vierergruppen in Calopte- nus, the formula would be i ^ ^ r • ^^th the divisions following the formation of a Vierergruppe would therefore be reductions, and it would be quite immaterial whether the first di- vision gave rise to two cells a h and c d, or to the two cells a c and h d. In Calop- tenus the rings may be placed upon the spindle equator in either of the two posi- tions represented in Diagrams 1 and 2. This offers, pei'haps, an explanation and reconciliation of the contradictory views of Henking, Hertwig, Hacker, and others. As has been said, Henking holds that the first division is a reduction division, and the second an equation division, while most authors make the first an equation, and the second a reduction division. Henking ('91) did not, in his Pyrrhocoris paper, recognize the existence of Vierergruppen as a regular stage in maturation; but I feel justified by his Figure 20 in believing that they were really present in Pyrrhocoris, just as in Gryllotalpa, Caloptenus, etc. Xow, supposing the proper formula for the Vierergruppen to be \ i i \ i ^'^J might it not happen in dif- ferent nuclei, or in different chromatic groups of the same nucleus, that 1 Henking. 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 Harvard University. Museum of Comparative Zoology. Cambridge, Mass. : The Museum
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