A NEW FRESH- WATER ISOPOD OF THE GENUS MANCA- 

 SELLUS FROM INDIANA. 



B}^ Harriet Richardson, 



Collaborator, D'lrhion of Marine Inrrrlebrates. 



The species herein described as new was collected by Mr. L. E. 

 Daniels at Lily Lake, Laporte, Indiana, and sent to the United States 

 National Museum. J/ancaselhis danielsi is the fifth known species of 

 the genus Mancaf<ellus^ M. JyrachyuruK Harger, M. tnuix Haro-er, M. 

 iiiacroums Garman, and M. lineatux (Say) hav- 

 ing- been previous^ made known, and one sub- 

 species, M. tenax dilata Harger. 



Family ASELLID^E. 



MANCASELLUS Harger. 



MANCASELLUS DANIELSI, new species. 



Body ))roadly oval, with lateral parts of seg- 

 ments widely expanded. Head broader pos- 

 teriorly than anteriorly, the posterior jiart 

 ])eing as wide as the first thoracic segment. 

 Lateral margins have a deep and wide incision 

 which separates the narrower anterior lobes 

 from the widely expanded posterior lobes. 

 The eyes are opposite these incisions. The 

 frontal margin is produced in a small median 

 point, on either side of which is a shallow 

 depression, followed by another point, in turn 

 succeeded by a slight depression. The antennulse are short, reaching 

 only to the extremity of the fourth joint of the peduncle of the 

 antennae; the flagellum contains eight joints. The antenna? are ver}^ 

 long, extending nearly the entire length of the body. The mandible 

 is without a palp. 



The thoracic segments are subequal in length. The lateral parts 

 are wideh" expanded, with lateral margins entire. 



Fig. 1.— Mancaselh s 

 danielsi. x3|. 



Proceedings U. S. National Museum, Vol. XXV— No. 1294. 



505 



