CONTENTS 



No. 1. MARCH 



Carl, Gottfried Hartman. Studies in the development of the opossum 

 Didclphys virginiana L. I. History of the early cleavage. II. Forma- 

 tion of the blastocyst. Six text figures and eleven plates 1 



George T. Hargitt. Germ cells of coelenterates. II. Clava leptostyla. 



Eleven figures (two plates) 85 



Edward Phelps Allis, Jr. The so-called mandibular artery and the persist- 

 ing remnant of the mandibular aortic arch in the adult selachian. Two 

 figures 99 



Ethel Nicholson Browne. A comparative study of the chromosomes of six 



species of Notonecta. One hundred and fifteen figures (seven plates). 119 



Wm. a. Kepner and W. H. Taliaferro. Organs of special sense of prorhyn- 



chus applanatus kennel. Three text figures and two plates 163 



No. 2. JUNE 



VVm. Rees B. Robertson. Chromosome studies. I. Taxonomic relationships 

 shown in chromosomes of Tettigidae and other subfamilies of the Acrididae : 

 V-shaped chromosomes and their significance in Acrididae, Locustidae, and 

 Cryllidae : chromosomes and variation. Twenty-six plates 179 



H. S. Davis. The structure and development of a Myxosporidian parasite of 



the squeteague, Cynoscion regalis. Seven plates and seven text figures. . . 333 



Selig Hecht. Form and growth in fishes. Eleven figures 379 



Roy L. Moodib. The structure and growth of the Plesiosaurian propodial. Six 

 text figures and one plate 401 



Caswell Grave. Ophiura brevispina. II. An embryological contribution and 

 a study of the effect of yolk substance upon development and developmental 

 processes. Four text figures and one plate 413 



Stanley C. Ball. The development of Paravortex gemellipara (Graffilla 



gemellipara Linton). Sixteen text figures and nine plates 453 



No. 3. SEPTEMBER 



Vera Danchakoff. Studies on cell division and cell differentiation. I. 



Development of the cell organs during the first cleavage of the sea-urchin 



egg. Thirty-one figures (five plates) '^'^'^ 



John D. Kernan, Jr. The chondrocranium of a 20 mm. human embryo. 



Nine plates '^'^"^ 



Bertha E. Martin. Tooth development in Dasypus novemcinctus. Fifteen 



text figures and four plates "47 



