THE OSTRACODA, 



285 



about 200 fatlioms; taking this in combiuation witb (2), I infer that these smaller 

 specimens below 200 fathoms Avcre either dead, dying, or sinking to comj)lete their 

 last moult to Stage I. 



Turther, it Avould seem that, though a few specimens occurred as high as the surface 

 and throughout the epiplankton by day, 1.0 A.M.-7.0 p.m., yet the majority of specimens 

 lived below 100 fathoms, and only rose into the epiplanktou by night, 7.0 P.M.-4.0 a.m. 

 Analysis of the upper hauls yielded the following result : — 



At fathoms the average catch per hour was 6'U by day, r2 l)y night. 

 25 „ „ „ 0-1 „ 69-6 



50 „ „ „ • 5-5 „ 18-1 „ 



75 „ „ „ 15-3 „ 81-0 



100 „ „ „ 4.1 „ 12-2 



And, without insisting too strongly on the individaul figures, there can be little doubt 

 that, taken as a whole, they show a far greater population by night than by day. 



In summary, it appears probable that the younger stages were essentially of the 

 epiplankton and upper mesoplankton between and 200 fathoms, with a night centre of 

 distribution at 25-75 fathoms ; but the older stages were pm-ely mesoplanktonic *, 

 with a maximum between 750-500 fathoms. 



The curious rise in the number of small specimens between 400-750 fathoms will be 

 discussed later (p. 297). The whole distribution is very like that of rotmidata (p. 293). 



The specimens at or near the surface Avere too few and too inconstant to afford any 

 evidence for or against reaction to rain, &c. 



Conchcecia daphnoiues, Claus. 



average 



specimens 



per hour 



liaul. 



average 



specimens 



per 100 



fathom haul. 



The distribution presents some curious features. In the first place, all the epiplankton 

 captures were at night, except for a single specimen from 100 fatlioms at mid-day. 



* Of course if an adult lives at great depths, young specimens probably can also exist there, but it does not 

 follow that they do so. 



46* 



