38 



CYTOLOGY 



CHAP. 



It is not found, for example, in Tomopteris. Owing to its conspicuous 

 nature and to the fact that it is confined to the meiotic prophase, it early 

 attracted the attention of cytologists, by many of whom it used to be 

 considered diagnostic of the fact that syndesis was in progress. In 



Fig. i6. 



Meiosis in Lepidosiren (male). (Agar, Q.J.M.S., 1912.) A, P^ing spermatogomal nuc^^^^^ 

 spermatogonia! prophase ; D, daughter plate from a spermatogonia! anaphase ; E, restmg spermatocyte 1., 

 F, zygotene ; G, pachytene nucleus. 



consequence of this, the word synapsis proposed by Moore to cover the 

 whole of that period of meiosis in which syndesis occurs, has been applied 

 by many cytologists to its most conspicuous feature alone— namely, the 

 contraction just described. It has been thoroughly estabhshed, however, 

 that the contraction of the chromatin has no invariable relation to the 



