CONTENTS 



NO. 1 JULY 



Lewis R. Gary. The influence of the marginal sense organs on the rate of 

 regeneration in Cassiopea xamachana. Eleven figures 1 



S. O. Mast and F. M. Root. Observations on ameba feeding on rotifers, 

 nematodes and ciliates, and their bearing on the surface-tension theorj'. 

 Five figures 33 



Onera a. Merritt Hawkes. The effect of moisture upon the silk of the 

 . hybrid Philosamia (Attacus) ricini Boisd. d' X Philosamia cynthia 

 (Drury) 9 51 



H. B. Goodrich. The germ cells in Ascaris incurva. Eleven text figures 

 and three plates 61 



C. M. Child. Studies on the dynamics of morphogenesis in experimental 

 reproduction and inheritance. IX. The control of head-form and head 

 frequency in Planaria by means of potassium cyanide. Ten figures. . . . 101 



A. Franklin Shull and Sonia Ladoff, Factors affecting male-produc- 

 tion in Hydatina. One figure 127 



NO. 2 AUGUST 



W. G. Allee. Chemical control of rheotaxis in Asellus. Ten figures 163 



Charles Packard. The effect of radium radiations on the rate of cell divi- 

 sion .^ 199 



Charles W. Metz. Chromosome studies on the Diptera. II. The paired 

 association of chromosomes in the Diptera, and its significance. Eight 

 plates 213 



S. O. Mast and K. S. Lashley. Observations on ciliary current in free- 

 swimming paramecia. Six figures 281 



NO. 3 OCTOBER 



E. R. HosKiNS. The growth of the body and organs of the Albino rat as 

 affected by feeding various ductless glands (thyroid, thymus, hypoiihy- 

 sis, and pineal). Four charts 295 



E. I. Werber. On the blastolytic origin of the 'independent' lenses of some 

 teratophthalmic embryos and its significance for the normal development 

 of the lens in vertebrates. Two text-figures and two plates 347 



Ralph S. Lillie. The physiologj^ of cell-division. VI. Rhythmical changes 

 in the resistance of the dividing sea-urchin egg to hypotonic sea water 

 and their physiological significance 369 



E. P. GHURCiiiLii, Jr. The absorption of nuti'iment from solution by fresh- 

 water mussels. Thirty figures (two plates) 403 



A. R. MooRE. The mechanism of orientation in Gonium. Two figures. . . . 431 



iii 



