758 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [4] 



Tliey appear in many cases to be surface swimmers. I have myself 

 seeji schools of several thonsaiids of Daphniadw of a greenish yellow 

 color in the ditches south of Camden, N. J., swimming at the surface of 

 the water at midday in the bright sunlight. In the vicinity of Wood- 

 bury, in the same State, my friend Mr. W. P. Seal has taken great 

 numbers of abrightred colored Copepod, apparently related to the genus 

 Po7itella, and perhaps undescribed. They were suflBciently abundant 

 in some cases to impart a red tinge to the water. 



Brady (Monograph British Copepoda) observes in his introduction, 

 vol. i, page 9 : " The beds of fresh-water lakes seem to be very sparsely 

 populated with Copepoda, and as to swimming species it may, as a 

 general rule, be said that the weedier the pool and the smaller its ex- 

 tent the more abundant in all probability the Entomostraca. 



" Many of the marine species pass their life apparently near the sur- 

 face of the open sea, and some of these, such as Calanus Jinmarchiafius, 

 Gunner, and Anomolocera Patersonii, Templeton, are frequently found 

 in immense profusion, the first-named species having been said to form 

 a very important part of tlie food of the Greenland whale, and it is re- 

 markable that in the Arctic seas not only do the Entomostraca attain 

 an enormous development in point of numbers, but also in individual 

 size, Arctic specimens, for example, of Calanus finmarcliiamis and Me- 

 tridia armata being many times the bulk of those taken in our own lati- 

 tude." {I. c.) 



According to H. Woodward, in his article Crustacea, Eucyclopajdia 

 Britauuica, the fecundity of the Copepoda is truly surprising. " Cyclops 

 quadricornis is often found with thirty or forty eggs on each side, and 

 though those species which have but a single ovisac do not carry so 

 many, their number is still very considerable. Jurine isolated speci- 

 mens of Cyclops, and found them to lay eight or ten times within three 

 months, each time about forty eggs. At the end of a year one female 

 would have produced 4,442,189,120 young! Cetochilus is so abundant 

 both in the northern seas and in the South Atlantic as to serve for 

 food to such an immense animal as the whale. They color the sea for 

 many miles in extent, and when the experienced whaler sees this ruddy 

 hue upon the ocean he knows he has arrived at the 'pasture of the 

 whales.' They are to be seen in vast quantities off the Isle of May, in 

 the Firth of Fot th, during the summer mouths. Many Cetacea are at- 

 tracted thither, and vast shoals of fish also come to feed upon them. 

 One anomalous type of free Copepod is the Notodelphys ascidicola, de- 

 scribed by Allman, which is found swimming freely in the branchial 

 sack of Ascidia coinmunis." 



The writer, in passing, would remark that he has frequently met with 

 Copepoda swimming freely in the ventral part of the branchial space 

 of Mya arenaria, in which the animals were probably not parasitical or 

 commensal, but had been drawn from without into the respiratory space 

 of the mollusk through the iucurrent part of its siphon. 



