484 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 42. 



Fig. 5.— Cambarincola maceodonta. Three cocoons, showing the 

 variation and irregularities. 



median line in the posterior portion of the segment, leaving segment 7 

 near the dorsal wall of the body cavity; continuing in the anterior 

 portion of segment 8 much narrower, crossing again to the left side 

 and descending to the center of the segment, enlarging in the posterior 

 portion of the segment, but leaving segment 8 near the center as a small 

 tube; the rectum beginning in segment 9, passing diagonally through 



this segment to its 

 dorsal wall, opening 

 dorsally in the me- 

 dian line in the an- 

 terior portion of seg- 

 ment 10. 



Living animals 

 colorless and quite 

 transparent except- 

 ing the alimentary 

 canal (which was a 

 pale green in the 

 specimens ob- 

 served) , and the 

 gonads; body quite 

 contractile. 



Cocoons subspherical and borne by a short pedicle; distal portion 

 of the capsule produced into a slender, pointed peak which usually 

 shows a basal enlargement; total length of cocoon and pedicle 0.7 to 

 0.9 mm. ; length of pedicle about 0.14 mm. ; length of peak about 0.08 

 mm. ; average width of cocoon 0.3 mm. 



Found on almost any part of the exterior of Cambarus diogenes 

 Girard, particularly on the ventral surface. No specimens were found 

 in the gill chambers. 



This species maybe separated from C. pMladelphica (Leidy), the 

 nearest related species, and its systematic position determined from 

 the following key. Its general anatomy, with the exceptions already 

 made in the description, is practically the same as that of Bdellodrilus 

 iUuininatus (Moore), which has been elaborately treated by Moore. ^ 



KEY TO THE KNOWN UISCODRILID^ OP THE UNITED STATES EAST OF THE ROCKY 



MOUNTAINS. 



a}. Dorsal and ventral dental plates similar; anterior nephridia with separate dorsal 



openings Branchiohdella Odier. 



6^ A parr of cup-shaped organs on the latero- ventral surface of both segments 8 and 



9; alimentary canal rather straight B. pulcherrima Moore. 



b^. No cup-shaped organs on segments 8 and 9; alimentary canal much convoluted 

 near its posterior end; posterior half of the body distinctly wider than the 

 anterior half B. instahilia Moore. 



' Journ. Morph., vol. 10, 1895, p. 497 et seq. 



