No. i.] REPRODUCTIVE ORGANS OE D/OPATRA. 121 



DlOPATRA MAGNA Sf>. 11. 



Body flat, elongated ; first five or six somites convex and 

 elevated dorsally, so that mouth is terminal ; buccal somite 

 small, widened at sides, as narrow dorsally as first setigerous 

 somite, bearing at middle of each side a smooth tentacular 

 cirrus as long as first two setigerous somites. Head withdrawn 

 into buccal somite; palps large, globose with nodules anteriorly; 

 antennas smooth, with short annulated bases about as long- as 

 first setigerous somite ; median antenna and intermediate ones 

 four times as long as tentacular cirrus, outer one about half 

 length of median one ; tentacles cylindrical, with conical tips, 

 and as long as bases of antennas. Anterior five parapodia very 

 stout, three directed forward. Branchiae pectinate, beginning 

 upon the sixth setigerous somite as a simple filament ; pinnules 

 increasing to about 12 by the 13th somite, where the branchiae 

 meet over the back ; posterior to middle of body the number of 

 pinnules decreases gradually, the branchiae becoming flabellate, 

 bifid, and finally simply filiform on the posterior somites. 



Setae in first five parapodia, about 13 to each, imperfectly 

 jointed, with the hooked tip and tooth below it enclosed in a del- 

 icate hood : other parapodia bear about 30 simple, pointed setae, 

 two stout ho'ok setae, and delicate, asymmetrical, finely serrated, 

 chisel-shaped setae. Jaw pieces dark; lower jaws with whitish 

 tips, indented on the edge ; dental plates with 8 teeth on right 

 and 7 on left ; large pair of paragnaths with 8 teeth on right and 

 6 on left, unpaired piece on left with 8 teeth; two small pairs of 

 paragnaths, the one smooth, the other with a rounded boss. 



Color dark, except anterior end, which is flesh color with 

 sprinkling of dark dots ; branchiae dark brown ; antennae red- 

 dish brown ; body translucent posteriorly ; posterior intestine 

 full of dark fragments of eel-grass, etc. Anus very large ; anal 

 cirri shorter, more slender than median antenna. 



Length, up to 1 m. ; breadth without parapodia, 16 mm. ; 

 median antenna, 10 mm. 



Found in pure sand of outer parts of "Bird Shoal," Beaufort, 

 North Carolina. Constructing stout, conspicuous tubes project- 

 ing vertically some inches above sand, and turned to one side at 

 orifice. 



Eggs laid in greatly elongated, large cylindrical mass of jelly. 

 Youns: often constructing small tubes on outside of those of adult. 



