Katharine Foot and E. C. Strobell 223 



the " Samenmuttenzelle " (spermatocytes 1st order of authors) has 

 attained its growth the chromatin is distributed as a delicate " Maschen- 

 werk" (cf. his Figs. 10 and 11 with our Photo. Ill, Plate VII). He 

 next figures and describes the chromatin as a coil with a single longitud- 

 inal split (Fig. 12), this coil dividing transversely into half the number 

 of somatic chromosomes, each of the bivalent segments representing two 

 somatic chromosomes attached end to end, later their free ends uniting 

 to form rings, these rings showing the same longitudinal split which he 

 demonstrated in the coil. He is uncertain, however, whether this longi- 

 tudinal split foreshadows the first or second division. He says : " Es 

 kann folglich die eine der beiden Trennungen der Chromosomen auf diese 

 vorseitige Spaltung des Chromatinfadens zuriickgefiihrt werden; ob dies 

 nun aber die erste oder die zweite Theilung ist, kann nach den Priip- 

 araten nicht mit Sicherheit entschieden werden, ich mochte eher an die 

 zweite Theilung denken," p. 113. 



Montgomery's, 'oi, '04, interpretation of the prophases studied in a 

 variety of forms, is supported by AUolohoplwra in the longitudinal split 

 of the coil (cf. Montgomery's '04, Figs. 10 and 11 with our Photos. 114 

 and 115, Plate VII), and the separation of the univalent chromosomes at 

 the first division, but this egg does not support Montgomery in certain 

 points in which his observations differ from those of Vom Rath, Riickert 

 and Hacker. These points are clearly stated by Montgomery, '04: 

 " Eiickert, '94a, and Hacker and others after him, concluded that there 

 was a continuous chromatin spireme preceding the first maturation mitosis, 

 and that the apparent reduction in number of the chromosomes is effected 

 by this cliromatin spireme segmenting into half the normal number of 

 chromosomes. I showed for Peripatus, '00, on the contrary, that a 

 continuous linin spireme is present at this stage but not a continuous 

 chromatin spireme, and that the bivalent chromosomes are produced by a 

 later conjugation without the formation of a continuous chromatin loop. 

 According to Riickert it is a case of chromosomes already closely con- 

 nected remaining so; according to me, of chromosomes not in contact at 

 first, becoming so secondarily. Hence I spoke of this act as the con- 

 jugation of the chromosomes, and argued that this is the important 



bivalent chromosomes show a tendency to unite into a ring and in some cases 

 nearly all the eleven chromosomes are rings (Photo. 122), and sometimes not 

 a single ring is formed, Photos. 116 and 118. This by no means disproves 

 Baumgartner's conclusions, for the variety of shapes of the chromosomes 

 of AllolohopTiora may be due to mechanical disturbance of the living form 

 incident to the technique. This point can be determined only by the study 

 of living chromosomes. 



