245 



4. D. retrocurva Diaph. brachyurum Ceriodaphnia lacustri.'< Birge. Leplodora 

 hyalina Lillj-, Holopedium gib))€i'um, one specimen. 



5. Diaph. brachyurum, Sida crystallina, Cer. lacustris. 



6. Holo. gibberum, Diaph. brachyurum, D. retrocurca, Algae like No. 1. 



7. Diaph. brachyurum, D. retrocurca, Cer. (acustri.^, Leptodora hyalina. 

 Great number of Epi.ichura lacu.<tris, far more than I ever saw before. 



8. D. retrocurva, Sida crystallina, Diaph., brachyurum. 



9. Diaph. brachyurum, D. retrocurva, not an extreme form, D((phnia hngiremis 

 Sars, Sida crystallina, very few. 



Most of these species are predictable, that is, they would be found in al- 

 most any pelagic collection from this general region. I do not think that H. 

 gibberum has been found so far south as this collection shows it. Cer. lacu-itris has 

 not been found outside of Wisconsin before. The specimens are much more thin- 

 shelled than those which I have seen before. It is remarkable that D. retrocurva 

 is far more numerous than is D. hyalina. The reverse has been true in all lakes 

 which I have studied, except Pine Lake, Wisconsin. In most of the bottles ex- 

 amined it was difficult to tind D. hyalina, while the other species was quite plentv. 

 It is to be noted that this species of Forbes is really a variety of D. kahlbergien- 

 si'.v Sch, but as the form is well marked and the full name intolerably long, I 

 have quoted it by the varietal name only. 



D. longiremis has been found before only in Lake Geneva, Wisconsin. In 

 size, form and shape of head it exactly agrees with my figures and description in 

 Trans. Wis. Acad.; Vol. IX, p. 299, pi. XI, figs. 4-10. 



In all bottles there were many Cyclops and Diaptomu.i, and in one, as already 

 noted, large numbers of Epischura. 



I should gladly write more, but have been too busy for a longer report. Will 

 send bottles to Marsh for Copepods and try to get up a full account later. 



Very truly, 



E. A. Birge. 



Data of the lots of specimens numbered in the above letter: 



I. Taken Aug. 28, 1S95, between 1 and 2 p. m., from surface of water. Killed in 

 picro-sulphuric acid. Preserved in 70 per cent, alcohol. 



II. Taken June 27, 1895, at 8 a. m. Skimmed from surface of water, using Xo.2 Bolt- 

 ing Cloth. Killed in picro-sulphuric acid. Preserved in 70 per cent, alcohol. 



III. Taken Aug. U, 189-5, at 5 P. M. Depth of haul, 60 ft. Killed in picro-sulphuric 

 acid. Preserved in 70 per cent, alcohol. 



IV. Taken .July 27,1895. Skimmed from surface of water, using Xo. 2 Bolting Cloth. 

 Killed and preserved in 10 per cent, formalin. 



V. Taken June 27, 1895, at 8 a.m.- Skimmed from the surface with a Xo. 2 Bolting 

 Cloth net. Killed and preserved in 10 per cent, formalin. 



