Feb., 1907.] Notes on a Sandusky Bay Shrimp. 75 



latter were found in greatest abundance two or three hundred 

 feet from shore where the water was three or four feet deep. 

 (The coves of Sandusky Bay are as a rule quite shallow). Tow- 

 ing near the surface was unsuccessful, a few were secured at the 

 bottom, but most were taken midway, and somewhat nearer the 

 bottom. 



The most abundant vegetation hi the coves of Sandusky 

 Bay is included in the following hst: 



Mvriophyllum spicatum L. (Very abundant). 



Vallisneria spiraHs L. (Very abundant.) 



CeratophvUum demersum L. (Abundant.) 



Naias flexihs (Willd.) Rost & Schmidt. (Abundant.) 



Philotria canadensis (Mx) Britt. (Water Weed.) (Very 

 abundant.) 



Potamogeton perfoHatus L. (Common; also five or six other 



species). 



Pontederia cordata L. (Pickerel weed.) 

 Zizania aquatica L. (Wild Rice.) 

 Scirpus lacustris L. (Great Bulrush.) 

 Nymphaea advena Soland. 

 Castalia tuberosa (Paine) Greene. 

 Nelumbo lutea (WiUd.) Pers. 



Light Experiments. 



On Aug. 17, 1906, thirteen shrimps were taken and at once 

 placed in an aquarium two thirds full of water with a few pond- 

 weeds and sand on the bottom. The aquarium was then taken 

 into the dark room. Ten minutes after this it was examined 

 with an acetvlene gas lantern and the shrimps were found scat- 

 tered. Holding the lamp for a moment at one end there was 

 an immediate response, many swimming toward the light. The 

 shrimps were then left in the dark for an hour. 



2:46 P. M. Shrimps scattered. Within one minute five re- 

 sponded to the light, coming to the glass. (Light left in position) . 



2:55 P. M. Ten were at the light end, one within four inches 

 and two at the farthest end. The movement toward the light 

 was not a darting, but a ghding motion. When the glass was 

 reached the motion was continued from side to side, but in one 

 or two minutes the shrimps came to rest. 



3:09 P. M. All seemed to be in about the same position. 



4:15 P. M. The remaining shrimps were nearer the light. 

 The light end of the aquarium at this time was fairly plastered 

 with pond-snails which happened to be in the aquarium, eleven 

 out of a possible fourteen had crawled up the glass. 



4:45 P. M. Only two shrimps remained at the darker end. 



6:00 P. M. The shrimps were pretty w^ell scattered again. 

 Those that could be observed had their heads turned awav from 



