44 



Stanley K. Sessions and John E. Wiley 

 L P A M 



Fig. 4. Diagrammatic representation of the four kinds of Y-chromosomes 

 found in Necturus. L-N. lewisi, P = N. punctatus, A = N. alabamensis, M = N. 

 maculosus. Light, stippled, and dark regions represent euchromatin, lightly 

 stained C-band heterochromatin, and darkly stained C-band heterochromatin, 

 respectively. 



Fig. 5. Mitotic, unstained chromosome spread of a female N. beyeri showing 

 12 telocentric chromosomes. Two bi-armed chromosomes were squashed away 

 from the main spread and are not included. Scale = 10 micrometers. 



