M'CLUNG : SPERMATOCYTE DIVISIONS OF THE ACRIDID.E. 91 



the term "synaptic phase," intended it to designate that period of the 

 prophase during which a fusion of the chromosomes existing in the 

 si^ireme takes place in such a way that half the normal number arises 

 from its subsequent division. Since it is at this time that the con- 

 centration of the chromatin at one side of the nucleus takes place, 

 under some conditions, the term "synapsis" has come to apply to this 

 massing of the chromatin. Montgomery attaches the term to a con- 

 dition of the telophase in which the still persisting chromosomes are 

 collected at one side of the nuclear cavity. It is generally understood 

 that synapsis does not occur except during the spireme condition of 

 the nucleus. This is expressed by Hacker (4) i'l the following 

 language: "Mit dem von Moore stammenden Au.sdruck 'synai)sis' 

 bezeichnet man neuerdings vielfach ein Stadium dcr Mutterzellkerne, 

 in welchem der in der Kegel shon langsgesijaltene, aber wahrscheinlieh 

 noch unsegmentierte, Chromatinfaden auf einer Seite des Kernraums, 

 gewohnlich im Umkreis des Nucleolus, einseitig kontrahiert er- 

 scheint." 



While dwelling upon the subject of "synapsis," I should like to 

 state that I consider the appearance itself to be an artefact. Doubt- 

 less Moore and Hacker are correct in their belief that the nucleus is 

 in a peculiar condition at the time when the contraction phenomenon 

 occurs, but that the chromatin exists in the living cell in the form of 

 a concentrated mass, I very much doubt. My study upon insect 

 spermatocytes leads me to this belief, for the following reasons : In 

 properly treated material no synapsis occurs. When observed, its 

 artificial character is evident because the mass of chromatin is always 

 to be found in the region of the nucleus opposite to the point at which 

 the fixing or dehydrating fluids had free entrance. Thus, in a freely 

 exposed follicle, the chromatin masses always lie toward the central 

 axis of the follicle. 



Montgomery follows his synapsis phase by the post-synapsis, in 

 which the mass of chromosomes becomes disentangled, and the liber- 

 ated elements lie free on the periphery of the nuclear vesicle. Its 

 termination yet witnesses no dissolution of the spermatogonia! chro- 

 mosomes and formation of a spireme thread from their substance. I 

 am not prepared to criticize these views concerning the Hemipteran 

 cells at this time, but in the Orthoi^tera I am sure no such occur- 

 rences are to be found. In these, the sperm atogonial chromosomes, 

 with the exception of one, rapidly disintegrate, and from their scat- 

 tered granules a very fine spireme thread is formed. In Hij)phcvs, 

 since the spermatocytes pass through the winter in this spireme stage, 

 any synapsis, if it occurred, would easily be found in the long follicles 

 filled with the prophase spiremes in various stages of advancement. 



