CONTENTS 



No. 1. DECEMBER 



Ethel Browne Harvey. A review of the chromosome numbers in the 



Metazoa. Part 1 1 



C. M. Child. Experimental control and modification of larval develop- 



ment in the sea urchin in relation to the axial gradients. Eight plates. . 65 

 Roy L. Moodie. On the sinus paranasals of two early tertiary mammals. 



Five figures 135 



F. X. Williams. Photogenic organs and embryology of Lampyrids. Ten 



plates 145 



E. A. Baumgartner. The development of the hypophysis in reptiles. 



Sixty-eight figures 209 



Fernandas Payne. A study of the germ cells of Gryllotalpa borealis and 



Gryllotalpa vulgaris. Five text figures and four plates 287 



No. 2. MARCH 



E. R. Hoskins. On the development of the digitiform gland and the post- 

 valvular segment of the intestine in Squalus acanthias. Thirty figures. . 329 



Walter E. Camp. The development of the suprapeiicardial (postbranchial, 

 ultimobranchial) body in Squalus acanthias. Twenty-nine figures 

 (two plates) 369 < 



Grace A. Wells. The skull of Acanthias vulgaris. Twenty-two figures ' 

 (three plates) 417 



E. Eleanor Carothers. The segregation and recombination of homologous 

 chromosomes as found in two genera of Acrididae (Orthoptera). Five 

 text figures and fourteen plates 445 



P. W. Whiting. The chromosomes of the common house mosquito, Culex 



pipiens L. Seven text figures and seven plates 523 



Robert T. Hance. The somatic mitoses of the mosquito Culex pipiens. 

 Two plates 579 



George T. Hargitt. Germ cells of coelenterates. III. Aglantha digitalis 



IV. Hybocodon prolifer. Fifty-five figures (six plates) 593 



D. B. Casteel. Cytoplasmic inclusions in male germ cells of the fowl tick, 



Argas miniatus, and histogenesis of the spermatozoon. One text figure 

 and eight plates 643 



