CHROMOSOME STUDIES 233 



107, 108) ; Tomopteris, by the Schreiners ('06, figs. 22, 23, 25, 

 26, 29-35); Salamandra, by the Schreiners ('06, figs. 10-13; '08, 

 figs. 13-22) ; Batrachoseps, by Janssens ('05, figs. 57-60) ; 

 Amphibia, by Montgomery ('03, figs. 2-4) ; and LiHum, by Gre- 

 goire ('99, figs. 5-8; '07, figs. 12-19). With the exception of 

 Davis, Montgomery, and Granata, these authors have considered 

 this stage to be the result of the side-to-side pairing of homol- 

 ogous chromosomes now beginning the disjoining process, and 

 I agree with them. 



In the later stages four strands were seen in each spireme 

 (figs. 164-167). Such spiremes are similar to the tetrads which 

 Carnoy described in 1887 for the nematodes Ophiostomum, 

 Ascaris clavata, and Ascaris lumbricoides as being formed by 

 a double longitudinal division of the single primary maturation 

 chromosome rod, and to those seen in Ascaris megalocephala 

 in the same year by Boveri ('87), who gave the same explanation 

 of their origin. Granata likewise found, in Pamphagus, the 

 early prophase chromosomes of the first spermatocyte to con- 

 sist of four longitudinal parts, the result of splitting in two longi- 

 tudinal planes at right angles to each other. I do not agree 

 with him in regard to the origin of tetrads, nor in regard to the 

 time and manner of reduction, but I am able to confirm his 

 figures. 



In Syrbula there were eleven of these spiremes, in Chorthip- 

 pus, eight, corresponding respectively to the number of pairs 

 of autosomes in each species. Polarization of the material in 

 the spiremes was shown by the presence of the polar granules 

 (knobs). These were terminal in Syrbula, a pair for each of 

 the eleven chromosomes. In Chorthippus but five showed 

 terminal knobs. The three remaining (long) spiremes each 

 showed two pairs of the granules or thickenings, located at the 

 point along the chromosome corresponding to the position of 

 the apices of the Vs. which had conjugated to produce them. 

 The number of knobs in Chorthippus will therefore be seen 

 to be eleven, as in Syrbula, consisting of the five terminal pairs 

 on the short spiremes and the two non-terminal pairs on each 

 of the three long spiremes. In the two-strand condition (fig. 



