On the anatomy of Ocnerodrilus. 11 



brieulus and RJiyncJiehnif, which are often seen Kwimniing with great 

 rapidity. 



Like other worms of this family Onierodrilus is also sometimes 

 fomid hidden in the mud, but with its tail motionless extending above 

 the bottom. 



Hab. Fresno County, California, in an irrigation box, where it 

 was found climbing on the alyascovered boards or hiding in the crevices 

 of the same. Mature in the latter part of October. 



Expliiiiiitioii of the figures. 



PL I. 



Fig. 1: Ocncrodrihis occ/dc>ii(ilii> uat. size. 

 » 2: two of its spiues, highly magnified, 

 w 'à: the efferent ducts and receptacle. 



» efd = efferent ducts. 



» eff = eft'erent funnels, or the interior openings of the ducts. 



» gp = genitalporus, in which the ducts and the receptacle unite. 



» rs = receptacuhim seminis. 

 » 4: Receptacuhim seminis. The lower end marked with a -|- is a continuation 



of the receptacle as represented in fig. 3. 

 » 5: A part of the alimentary système. 



» gl. = glands in the setigerous segments 2 to 6. 



» m = muscles between the integuments and the dissepiment in the T"" segment. 

 In the 7 segment are also seen the two lateral sacklike appendices, 

 opening in the oesophagus. 



» it = intestine. 

 » 6: The intestine in some of the posterior segments of the body. 

 » 7: a part of the upper side of the supra-oesophagial ganglion, showing the 



windings of the dorsal vessel. 

 » 8: the front part of the worm, showing the vascular system. 



» o = mouth. 



» Ic = cephalic lobe. 



» s.b. = buccal segment. 



» 1 — 11 = the first 11 segments of the body. 



» 1. b. = lateral branches of the dorsal vessel. 



» cc = hearts. 



» p. V. = perigastric vessels. 



» g. V. = gastric vessels. 

 » 9: The reproductive organs in their natural position. 



» 7 — 25 = numbers indicating the setigerous segments. 



» m = muscles. 



