208 robert h. wolcott: 



On either side of the genital area is a large nipple-like papilla, which 

 varies in prominence, and which, according to Piersig, can be retracted 

 by a muscle running to it from the last epimei'on. Koenike (81b) believes 

 these papillae to contain highly developed epidermal glands. 



MEASUREMENTS, 



Male. juv. Male Female Female 



Grand Rapids, Mich. Beaver I'ds. Beaver I'ds. Lake St. Clair. 



Length of body, 0.367 mm. 0.701 mm. 0.835 mm. 1.002 mm. 



Length of leg I, 0.683 mm. 1.234 mm. 1.357 mm. 1.596 mm. 



Length of leg II, 0.842 mm. 1.525 mm. 1.657 mm. 2.081 mm. 



Length of leg III, 0.632 mm. 1.193 mm. 1.285 mm. 1.632 mm. 



Length of leg IV, 0.872 mm. 1.596 mm. 1.708 mm. 2.112 mm. 



Length of palpus, 0.357 mm. 0.393 mm. 0.403 mm. 



Atax crassipes was first met with Sept. 1st, 1893, in ma- 

 terial dredged over a bed of Chara in Anchor Bay, Lake St. 

 Clair, at a depth of about 3 meters. Specimens were again 

 secured near the same locality on the 3d, and in that vicinity 

 again on the 12th, at a depth of 5 meters. It was collected in 

 the southwestern part of the lake on the 8th and 10th at 

 depths of 5 and 6 meters respectively, and off Point Pelee 

 Island, Lake Erie, on the 17th, at a depth of 5 meters. Alto- 

 gether 29 specimens were secured. It appeared to be of 

 general distribution over the Chara which carpets the bottom of 

 Lake St. Clair, a lake which though of an area of 410 sq. miles 

 is over its deeper portion only about 6 meters in depth. 



During the summer of 1894, specimens, parasitic as well as 

 free, were collected at several points in Northern Michigan. 

 They were found in Round Lake at Charlevoix, July 9th to 

 13th, at depths of 16 to 18 meters, in limited numbers; July 

 31st a specimen was secured in bottom collections from Lake 

 Michigan off Fisherman's Island, a few miles west of Charle- 

 voix, at a depth of about 10 meters, and on August 18th 

 the species was obtained in bottom tows in Lake Michigan 

 between Beaver and High Islands at depths of 10 and 23|- 

 meters. Aug. 6th the species was found at Twin Lakes and 

 "26 " Lake, small inland lakes near Charlevoix, on Aug. 21st 

 at Susan Lake, another similar lake in the vicinity, and in 

 material collected on the same day at Intermediate Lake, also 

 not far distant. Sept. 5th Dr. R. H. Ward collected specimens 



