N o. 2 . ] BA TRA CHOSEPS A TTENUA TUS. \ o 7 



formed around the nucleus at the time of the anaphase. The 

 archosome moves away and carries with it the fibers, which 

 pull away the false nuclear membrane, thus causing a vacu- 

 ole to form around the nucleus. The object of all this is 

 probably to enable the nucleus to develop without the interfer- 

 ence of surrounding structures. These fiber cones are fre- 

 quently very numerous, as many as seventeen having been 

 counted in a single cell. They are of large size and cause 

 the cell membrane to be pushed out. 1 



The spindle bridge, which connects two or more cells, con- 

 sists of the remnant of the central spindle. As the spindle 

 bridge exists only in cells which commence the same phase of 

 mitosis at the same time, it is probable that the purpose of the 

 spindle bridge is to time or regulate the commencement of this 

 mitosis. The mid-body of the spindle bridge serves probably 

 as a storage reservoir for the cytoplasm of the spindle bridge. 



VARIETIES OF CELLS. 



The testes of Batrachoseps contain four distinct varieties 

 of cells, as follows : polymorphous spermatogonia, auxocytes, 

 spermatocytes, and spermatids. These originate one from the 

 other in the order mentioned above. Of these varieties there 

 are one or more generations. They are characterized as 

 follows : 



Polymorphous Spermatogonia. - - These possess a perfect rest- 

 ing stage in which the nucleus is polymorphous as regards form, 

 being greatly indentated and folded during the perfect resting 

 stage. The nucleus during this stage contains neither chromo- 

 somes nor chromomeres, the chromioles being scattered about 

 and not connected with the chromoplasts. These cells give rise 

 to several generations of cells of the same nature, with the ex- 

 ception that there is no perfect resting stage like the one in the 

 mother-cell, and that consequently the nucleus is not folded, 

 but perfectly even, round, or oblong. The mitosis of the poly- 



1 Fiber cones of similar appearance, but of a different nature, have been de- 

 scribed by botanists from the pollen cells of higher plants. These cones, however, 

 do not possess archosomes. 



