620 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.47. 



turned upwards and backwards against the dorsal surface of the 

 trunk; eggs in eight rows at the base and four at the apex, about 100 

 eggs in each sack. 



Total length (egg strings excluded), 7 nun. Length of cephalo- 

 thorax, 3.4 mm.; of trmik, 3.6 mm.; of egg strings, 4.25 mm. Width 

 of cephalothorax, 3.15 mm.; of trmik, 3.25 mm.; of bulla, 3 mm. 



Color a pale grayish-white; the bulla and pedicel brown. 



Male. — Unknown. 



First copepodid larva. — Cephalothorax narrower and more elon- 

 gated than in amhloplitis, blmitly rounded anteriorly and irregularly 

 trmicated posteriorly. Notches between the head and first thorax 

 segment at about the center of each lateral margm; second thorax 

 segment half the width of the cephalothorax, with a concave pos- 

 terior margin; third segment half the width of the second, and 

 carrying near its posterior margin on either side a smgle spine; fourth 

 segment the narrowest; anal laminae relatively large, each tipped with 

 two long and two or three small and much shorter setae; first antennae 

 turned back along the margin of the cephalothorax. Total length, 

 0.92 mm. Cephalothorax, 0.7 mm. long, 0.32 mm. wide. 



{corpulentus, stout, corpulent). 



Remarks. — This species was first collected and described by Kelli- 

 cott in 1880 and was called by him the gill heiTing-sucker. 



Many specimens were obtauied from different species of whitefish 

 in Lake Erie, Lake Michigan, and Lake Ontario during the summer 

 of 1894. These were identified by Prof. R. R. Wright, Mr. G. G. 

 Gurley, and Dr. Richard Rathbun. Unfortunately none of the 

 specimens appear in the collection of the L^nited States National 

 Museum, but the species is so common that a good supply of typical 

 specimens of both sexes could easily be obtamed. This species may 

 be recognized by the corpulent appearance of both the head and the 

 trmik, which are approximately the same length and width, by the 

 large maxillipeds which reach beyond the frontal margin of the 

 head, and by the very broad and disk-like bulla. 



ACHTHERES MICROPTERI Wright. 

 Plate 34, figs. 64 to G7; plate 35, figs. 68 and 69. 

 Achtheres micropteri Wright, 1882, p. 249, pi. 2, figs. 1-11. 



Host and record of specimens. — Five females from the gills of the 

 small-mouthed black bass, Micropterus dolomieu, at Burton's Land- 

 ing, Kankakee River, Indiana, August 19, 1909, No. 39618, U.S.N.M. 

 Five females from gills of large-mouthed black bass, M. salmmdes, 

 at English Lake, Kankakee River, August 9, 1909, No. 39544, 

 U.S.N.M. Three females from same host at Lake Maxinkuckee, 

 Indiana, July 29, 1906, No. 39552, U.S.N.M. Fifteen males and 

 females from the same host at Constantia, New York, April 26, 1911, 



