y 



III. T. H. MORGAN. 



Further Experiments on the Regeneration of 



Tissue composed of Parts of Two Species . 111-119 



IV. C. B. DAVENPORT. 



Reviciv of Von Guaita 's Experiments in 



Breedin Mice ......... 121-128 



V. MARY HEFFERAN. 



Variation in the Teeth of Nereis . . . 129-143 



No. 4.- January, igoi. 



I. MARTIN SMALLWOOD. 



The Centrosome in the Maturation and 



Fertilization of Bui la Solitaria . . 145-154 



II. J. PLAYFAIR McMuRRicn. 



Contributions on the Morphology of the 

 Actinozoa. VI. Halcurias Pilatus and 

 Endocoelactis ..... i55- l6 3 



III. SAMUEL J. HOLMES. 



Observations on the Habits and Natural 



History of AmpJiithoe Longimana Smith 165-193 



No. 5. -- February, igoi. 



I. LEON J. COLE. 



Notes on the Habits of Pycnogonids . . . 195-207 



II. AIII.GAIL C. DIMON. 



Experiments on cutting off Parts of the 



Cotyledons of Pea and Nasturtium Seeds 209-219 



III. CHAS. W. HARGITT. 



Variation among Hydromedusae . . . . 221-255 



