MctJioih in Plankton Investigations. 2;5 



Rafter, G. W. 

 '92. The Microscopical Examination of Potable Water. No. ]03, 

 Van Xtistrand's Science Series. KiO pp., 5 Pis., New York. 

 Reighard, J. E. 

 '94. A Biological Examination of T.ake St. Clair. Bull. Mich. 

 Fish Comra. No. 4. 60 pp., 2 Pis., and map. 

 Ward, H. B. 

 '96. A Xew Method for the Quantitative Determination of Plank- 

 ton Hauls. Proc. Am. ]Micr. Soc, Vol. XVII., pp. 255-200. 

 '96a. A Biological Examination of Lake Michigan in the Traverse 

 Bay Region. Bull. Mich. Fish Comm., No. G. 100 pp., 5 Pis. 

 Zacharias, O. 



'93-'96. I'orschungsberichte aus der Biologischen Station zu Plon, 



Theill.-IV. Berlin. 

 '95. Ueber die Wechselnde Quantitat des Planktons im (irossen 

 Planer See. Forschungsberichte a. d. Biol. Station zu. Plon, Theil 

 III., pp. 97-117. 



*EXPLANATION OF PLATES. 



Plate I. 



Fig. 1. Longitudinal section of plankton net. X ^4. 

 c.b.l. Cone of butchers" linen, s.l. Staj'-line. 



Fi.i. 2. 



Fig. 3.— Longitudinal section of head-piece of plankton bucket. X 1. 

 e. Eye. s. Silk. 



h.p. Ilead-piece. .s. /. Stay-line. 



n. c. Xet clamp. t. s. Thumb-screw. 



m. Thread, screwing v\ n. c. Wing of net clamp, 



into n of Fig. 4. 



*Plates I., II., III., and IV. were drawn by C. A. Kofoid and inked by Miss L. M. Hart. 



