1897.] NEW YORK ACADEMY OF SCIENCES. 387 



faA'orable conditions, and also that tlie vertical sounded by us 

 trans verses a variety of colors in the water that are due to the 

 absorption of the several elements of the light. 



It may be said in general, therefore, of the vertical distribu- 

 tion here recounted, that the surface strata present the greatest 

 numbers of living individuals, and furnish the most favorable, 

 although irregular, conditions for the growth and reproduction 

 of these organisms ; but in the case of the large diatoms bur- 

 dened with a large siliceous case there is a relatively rapid sink- 

 ing into the strata beneath, and in other diatoms the conditions 

 of growth seem to be well fulfilled in the lower strata. It is also 

 true that all the forms here treated except the Copepoda are 

 found alive throughout the whole extent of our vertical, i. e., 

 112 fathoms deep. 



We believe, moreover, that this is the lowest depth to which 

 this method of quantitative estimate has been carried, and that, 

 as it gives analysis of water over such considerable depths, it 

 calls attention to them as recipient areas for material in process 

 of sedimentation as well as for conditions of life and growth in 

 an environment quite removed from the surface. 



We refer, in closing, with gratitude to the cooperation of Pro- 

 fessor H. F. Osborn,b3^ whose provision in the Zoological Expe- 

 dition these collections were made possible. The identification 

 of the diatoms was kindl}^ aided by the photographs made by 

 Mr. 0. E. Schaffer, of Port Townsend, Washington, who fur- 

 nished very complete data in this respect for that locality. All 

 the labors of procuring apparatus, collecting the materials and 

 furnishing descriptive data referring to such work were done 

 by the junior author of this paper, while the quantitative esti- 

 mates, plottings and writing are the work of the senior author. 



Biological Department, Williams College, 

 WiLLiAMSTowN, Mass., Nov. 20, 1897. 



[Zoology of Puget Sound. Columbia University Contributions No. 7.] 



THE MATURATION AND FERTILIZATION OF THE 

 EGG OF ARENICOLA MARINA. 



By C. M. Child. 



The material forming the basis of this paper was collected 

 during the summer of 1896, at Puget Sound, by Mr. N. R. Har- 

 rington, of the Columbia Universit}' Expedition. My thanks 

 are due him for the opportunitj' of examining the material, and 

 I take this occasion to express ni}' obligation. 



