ANNELID GENUS CAMBARINCOLA — HOFFMAN 303 



like those of mesochorea. I would arrange these species in the follow- 

 ing order of advancement: ouachita, restans, and mesochorea, although 

 this is a merely relative sequence and does not imply a straight line of 

 descent. Despite its several distinctive characters, mesochorea has 

 been confused with both C. macrodonta and C. mtrea in earlier litera- 

 ture; it is probably the basis for many of Goodnight's records for both 

 macrodonta and philadelphica. 



Key to Species of the Mesochorea Group 



1. Spermiducal gland with a large, conspicuous, posterior deferent lobe at its 



midlength; body form somewhat xironodriloid (southeastern Kansas). 



Cambarincola ouachita, new species 



Spermiducal gland without a large median posterior deferent lobe, the deferent 



ducts entering the extreme ental end of the gland with no enlargement; 



body form distinctly cambarincoloid 2 



2. Body form normal for the genus, head smaller than the second body segment, 



body diameter increasing up to segment vi or vii (entire Mississippi River 



system) Cambarincola mesochorea, new species 



Body form unusual: head half again as thick as largest body segment and as 

 long as first five segments combined; all body segments of essentially the 

 same diameter (northeastern Arkansas). 



Cambarincola restans, new species 



Cambarincola ouachita, new species 



Figures 8, 9 



Type specimens. — Holotype and one paratype, USNM 29937, from 

 Orconectes sp., collected 4.3 miles west of the Montgomeiy County line 

 on Kansas Hy. 168, Chautauqua County, Kansas by P.C. Holt, 

 July 8, 1958. 



Diagnosis. — A rather large member of the Mesochorea group, 

 differing from the other two by its larger, somewhat xironodriloid 

 body form, and also by the presence of a large and conspicuous pos- 

 terior deferent lobe on the spermiducal gland. 



Desckiption. — A medium-sized member of the genus, with a maxi- 

 mum length about 4.0 mm., the body rather elongated and parallel- 

 sided (in both specimens), somewhat reminiscent of the shape of 

 certain species of Xironodrilus. Segments ii-viii of about the same 

 diameter and length; caudal sucker about as wide as head or segment i. 

 Segments only a little longer than broad; prosomitcs not elevated 

 over level of metasomites and less than twice the length of the latter. 



Head of average size and form for the genus, as broad as segment i, 

 not quite as long as first three body segments, the peristomium set 

 off by a deep constriction and flared, but with entire margin. 



Jaws robust, anisomorphic, dental formula 5-4, teeth subhomodont, 

 acute. 



653871—63 3 



