104 
THIRTEENTH REPORT. 
cusses it quite in detail. This cell in Ceuthophilus agrees in general with 
the description given by him for the Acridiidae and Locustidae. 
The more or less definite pairing of the autosomes in the spermatogonia 
is in accord with the results of most other writers and seems to point 
to the fact that there is a double series of chromosomes, of approximately 
equal form and volume, one paternal, and the other maternal. 
Ceuthophilus apparently agrees with most other Orthoptera in having 
an end to end union of the chromosomes in synapsis and later, in 
the formation of the tetrads, by a splitting of the spireme thread. From 
the observations made the first maturation division is probably longi- 
tudinal and the second transverse. However, this could not be deter- 
mined with certainty so it is useless to discuss its relation with other 
forms in this respect. 
Ceuthophilus agrees with other Orthoptera in having an accessory 
chromosome which in the spermatogonia is larger than the autosomes. 
It remains compact throughout the growth period and tetrad formation 
stages, dividing in the secondary maturation division but not in the first. 
It can be traced with ease from the spermatogonia to a rather late 
spermatid stage. 
V. SUMMARY. 
There is near the distal end of each testicular follicle an apical cell 
surrounded by primary spermatogonia! cells. The secondary spermato- 
gonia are enclosed in cysts of connective tissue cells. The spermatogonia! 
chromosomes divide longitudinally, the accessory chromosomes with the 
rest. During the growth period the autosomes become diffuse whereas 
the accessory remains a compact body applied to the nuclear membrane. 
The spireme assumes a polar arrangement in the middle and late growth 
periods, and splits longitudinally at the beginning of tetrad formation. 
During the period of tetrad formation the accessory remains compact. 
The first maturation division is probably longitudinal, the second trans- 
verse. The accessory chromosome divides in the second maturation divi- 
sion and not in the first, one-half of the sperms therefore contain an 
accessory chromosome and the other half do not. 
VI. LITERATURE LIST. 
Baumgartner, W. J. : 
1904. Some New Evidences for the Individuality of the Chromo- 
somes. Biol. Bui., Vol. VIII, 1904, p. 1-29. 
Davis. If. S. : 
1908. Spermatogenesis in Aerididae and Locustidae. 
Bui. Mus. Com. Zoo., Harvard, Dec., 1908, p. GO-159. 
Otte, H. : 
1900. Sa men rei fung und Samenbildung von Lucusta viridissima. 
Die Samenreifung. Zool. Anz., Bd. 30,. 190G, p. 529-535. 
Ann Arbor, Mich., April, 1911. 
