ENTOMOSTRACA OF MINNESOTA. 131 



rather long and slender and have a well-marked flagellum. (Brady- 

 figures no llagellum.) The palp of the antennule is as in G. minutus. 

 The mandibular palp is small. The first pair of feet normal, rather 

 small; all the other swimming feet with two jointed inner rami, save 

 in the case of the male third foot. The fifth feet are exactly as figured 

 by Brady, save that there is a prominence or tooth of the basal seg- 

 ment near the point of attachment of the terminal joint which is quite 

 long. The sensory area of the head is oval and pointed. The male 

 antenna has a long flagellum, not, as figured by Brady, a very 

 short one. The egg-sac is very large, oblong. The animal seems to 

 fall shortof thesizeof the English species, though measuring upwards 

 of 0.65 mm. Our form is very well distinguished from any other spe- 

 cies. It is found in Lake Minnetonka, Lake Calhoun, and elsewhere. 



* Caiithocamptiis niiuiitiis Mueller. 



Plates XLVII, Figs. 7-21 ; L, Figs. 7, 8. 



Monoculus staphylinus — Jurine. 



Canthocamptus minutus — Lilljeborg, Baird, Sars, Uljanin, Brady, Herrick. 



Canthocamplus staphylinus — Claus, Fric. 



Canthocamptus minutus var. occidentalis — Herrick. 



A well-known species which has been frequently described and 

 seems quite circumpolar in its distribution. 



First mentioned from America in a paper by the writer in 1878 

 A pretty full description will also be found in the author's Types of 

 Animal Life. A very abundant species, frequent in muddy pools, but 

 somewhat variable in abundance. It may frequently be found in great 

 numbers in winter. 



[The following description, compiled from Types of Animal Life, is 

 inserted here for the convenience of those who are likely to use this 

 report as a manual. H. F. N.] 



Length about 1.0 mm. AntenniE a little longer than the first seg- 

 ment of the body; first three joints profusely covered with hairs; fourth 

 joint more slender than the preceding and terminating in a process 

 below, which bears, besides a long hair, a peculiar blunt bristle; fifth 

 joint shorter than the rest; the remaining three joints are spined at 

 definite points. The antennic of the male are geniculate; the three 

 basal joints are short while the three following joints are coalescent 

 and are followed by a hinge joint of two elongated segments. 



The antennules are two-jointed; the basal joint bears a two-jointed 

 palp; the terminal joint is covered with spines; at the end there are 

 three longer and curved spines, jointed in the middle, and the upper 

 furnished with three small spines at the curve. 

 9 



