430 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



certainh^ neither Crangoiiyx nor Xlphargus, but belongs to a distinct 

 genus for which I propose the name Bactrurm. C. flageUatus Bene- 

 dict differs from all the others in having the last two segments of 

 the urosome coalescent, and therefore can not be a Crangonyx, but 

 should stand as the t3-pe of a distinct genus which may be known as 

 Stygonectes. 



NIPHARGUS ANTENNATUS (Packard). 



The specimens from which this description is written were taken at 

 various i)laces within Nickajack Cave, and undoubtedly represent 



^^7**^ 



Fk;. 6.— Xiphargus 

 a RiglU liittTiil viow of adult female. 

 h Firet antenna of female, 

 c First antenna of male. 

 d Second antenna. 

 c Mandible. 

 / First pereiopod. 

 ;/ Second pereiopod. 



VTENNATITS. 



// Third pereiopod. 

 i Fifth pereiopod. 

 j First pleopod. 

 fc Second pleopod. 

 I Third pleopod. 

 wTelson. 



Packard's Craiigoin/.i' iinfrniKifiiiii described from this locality in 1881.' 

 They differ slightly in the specitic character and belong to a different 

 genus, but these differences are of such a nature as to make it seem 

 probable that they are the result of the poor material from which Dr. 

 Packard wrote his description. 



' Body slender, smooth. Head more elongate and less deep than 

 usual in this genus. Eye composed of a few slightly pigmented facets 



'Am. Nat., XV, 1881, p. 880. 



