STATE GEOLOGIST. 173 



being very small. Inner segment of the basal joint of the fifth 

 pair of feet in the female elongated, fringed, bearing two long and 

 three short apical setse; second or outer joint sub-ovate, finely 

 fringed internally; externally bearing six long marginal setae. In 

 the male the limb is smaller, the basal joint short, broad and hav-* 

 ing six short setae of equal length; second joint nearly like that 

 of the female. Caudal segments somewhat longer than broad; in- 

 ner seta about twice as long as the outer; anal operculum denticu- 

 late. Length .65 mm." Not found in America. 



Sp. 10. Canthocamptus palustris, Brady. 



(Plate K. Fig. 5.) 



A brackish-water species about .9 mm. long, found in a number 

 of places in the British Isles. The species presents several anom- 

 alies. 



The antennae of the female are 8-jointed; those of the male ro- 

 bust, the last joint forming a hook. The first four pairs of feet 

 have both branches 3-jointed; the fifth pair in the female are 2- 

 jointed, with a short and broad basal joint, the second joint being 

 sub-ovate, bearing five long apical setae; in the male the fifth pair 

 is obsolete, being reduced to a minute setiferous lobe. Caudal seg- 

 ments short, bearing two principal setae, the outer half as long as 

 the inner. 



Sp. 11. Canthocamptus minnesotensis. (Sp. n.) 



(Plate T. Figs. 1—6.) 



Since the manuscript of this genus was finished, a small species 

 has been found which seems undoubtedly distinct from any of the 

 above. A single pair were taken in a gathering from Bassett's 

 creek containing C. minutus in abundunce. Unfortunately the 

 characters of the swimming feet are not certainly known, but they 

 were apparently all three joiuted save the last. The antennas are 

 very short and thick, 8-jointed, with a long flagellum; the anten- 

 nules are of the usual form, and the mouth parts rather large. The 

 first pair of feet have the two rami of nearly equal length. The 

 form is moderately elongate. The caudal stylets are very short, 

 quadrate in outline and well armed with spines. The fifth foot of 

 the female has four long and two short spines on the inner lamina, 

 and the terminal joint has five unequal spines. In the male the 

 fifth foot has two spines on the lamina and six on the second joint,. 



