STUDY OF CHROMOSOMES OF LACHNOSTERNA. 95 



6. There are five atelomitic tetrads in the first maturation 

 division and five telomitic tetrads (including the sex pair). 



7. Cyst formation in the testis begins by the rapid division of a 

 single primary spermatogonium, so that all the cells within any 

 particular cyst are the descendants of a single cell. The visible 

 polarity of the cells seems to be established at the time of cyst 

 formation. 



G. ADDENDA. 



Since the manuscript of the foregoing study was written, the 

 work of Goldsmith 1 has appeared on the chromosomes of the 

 Cicindelidae. He has studied in all five species of this family 

 and finds that they agree in chromosome number. He has 

 described a double odd-chromosome which passes undivided 

 to one pole of the spindle in the first maturation division and 

 divides in the second maturation division giving rise to sper- 

 matozoa with ten and twelve chromosomes respectively. In 

 his study of the growth stages of the spermatocytes he has been 

 unable to find that the leptotene threads actually pair. His 

 figures of the synaptic stages are not clear and he makes no 

 decision as to the method of synapsis (parasynapsis or telosyn- 

 apsis). 



He describes the "early" spermatogonia as being arranged in 

 syncytia without any discernible cell-walls. He describes the 

 appearance within the syncytial cytoplasm of "cytoplasmic 

 fibrillar bridges." "With the increase in age and size of the 

 cells, these bridges become more dense and assume a definite 

 arrangement about a number of cells. This continues until the 

 entire tubule is subdivided into a large number of syncytia 

 cysts containing cells without perceptible cell walls" (p. 445). 

 Both his descriptions and figures of this peculiar method of cyst 

 formation lack in clarity. From his Fig. 5, I interpret the 

 "cytoplasmic fibrillar bridges "as being probably the persisting 

 spindle remains or mitosome of the previous division, and it is also 

 probable that the deeply staining bodies in the cytoplasm are 

 the mid-bodies (cell-plate) persisting with the mitosome. That 

 these "fibrillar bridges" are really spindle remains is further 



1 A comparative study of the chromosomes of the tiger beetles (Cicindelidae). 

 Jour. Morph., Vol. 32, No. 3, 1919. 



