168 TWELFTH ANNXTAL EEPORT. 



The ten species below enumerated are all that have fallen under 

 the author's notice, though others may have been mentioned. 



Key to the Genus Canthocamptus, 



>H j- „ I 2-)ointed i ^ '^™" ^<'"S; basal joint of 5th foot small C. gracilis, Sars. 



3 I "I ' 0.5 mm. long; basal joint of 5th foot long. Cftrewpes, Sars ^?). 



''I » \ 



g 5 j j-AntennsR thick C erassiis, Sars. 



B 2-iointed.o-i I Inner ramus of J ^ntennre ( C. trispinosiis, i Brady. 



f -i i i 3-ioiated. \ ^'^ ^°°^ 2-jointed. ( slender. j c. northumhricrcs, Rrady. 



12 I o" I ! Inner ramus of S Stylets rather long. C minutus. Mueller. 



s" \ ^ ' 1 2d foot 3-jointed. ' Styl. short, oval, C. illinoisetisis, Forhes 



o" I j Male antenna normal C. hibemicus. Brady. 



?. [ 3-jointed. ^ jyjj^jg antenna reduced, hooked at the end C. ? palustris, Brady. 



Canthocamptus elegantulus, C. mareoticus and C. horridus are 

 uncertain, probably referred to the wrong genus. C. stromii, Baird 

 ( = Dactylopus stromii,) C. rostratus, Claus (= Stenhelia iraa.) 

 C. virescens, C. linearis, and C. roseus of Dana, are marine Harpac- 

 ticidse of uncertain affinities. C. minutus of Claus is not sufficiently 

 described, but appears to be the earlier condition of C. minutus, 

 Mueller (C. staphynalis, Jurine). 



Sp. 1. Cauthocamptus gracilis, Sars, 



Is elongated linear, with the abdominal segments smooth. Caudal 

 stylets long and slender; external caudal seta about one-fourth the 

 inner. All the feet with two-jointed inner rami; outer branch of 

 fourth foot longer than the others, indexed; basal process of fifth 

 foot slightly expanded. Length 1 mm. 



At Decatur, Alabama, was found a species of Canthocamptus 

 which is different from any American species, and seems in many 

 points nearest the above but, unfortunately, only a hasty sketch 

 could be made at the time, and the notes are insufficient to define 

 it. The form is not remarkably slender; the first and second ab- 

 dominal segments are very large. The caudal stylets are slender 

 and elongated, the inner seta being very long and curved, while 

 the outer is quite short. The anal plate is covered with hairs only. 

 The antennae are normal, of moderate length, and the fifth foot has 

 but a narrow process at the base. 



1 Distinguished from the following by the presence of only three spines on the process 

 of the basal joint of the fifth foot. 



