1V CONTENTS 
No. 4. DECEMBER 
WiuuraAM Snow Miter. The air spaces in the lung of the cat. Four plates. 459 
E. Eveanor Caroruers. The Mendelian ratio in relation to certain orthop- 
(eramGhromosOmess mebOUimn plate sie sis ace 2)... ora eenen enews eee 487 
C. H. RicHarpson. Studies on the habits and development of a hymenop- 
terous parasite, Spalangia muscidarum Richardson. Seventeen figures. 513 
J. T. Parrerson. Polyembryonic development in Tatusia novemeincta. 
Thirty-five text figureésiand eleven plates........2.0 30-40-20. + see eee 559 
AnNnA Lowrey. A study of the submental filaments considered as probable 
electric organs in the gymnotid eel, Steatogenys elegans (Steindachner). 
LOW DeR AT RS Ses, vic: Gwe o 5 2h TE Ts cn. ako ca Menara sible ¢ 685 
