286 ANNELIDA POLYCH^TA ANDREWS. 



Among specimens taken at Beaufort is one that has reproduced a 

 new head and several somites, just as in the case described by Ehlers. 

 Moreover, sections show that the histological changes concerned are 

 much as Ehlers found them. Study of this same species on the Massa- 

 chusetts coast shov\ s that this reproduction of anterior or of posterior 

 end is a common occurrence and one of evident utility, almost a neces- 

 sity, considering the habit of the animal. Its tubes are raised above 

 the sand some inches and covered over with foreign objects, often quite 

 long pieces of eel grass. To collect this, the creature's anterior end is 

 protruded some distance from the protecting tube and must be a tempt- 

 ing morsel for fish, etc. At all events it is often cut off by some means. 

 This is the more likely to occur since the eyes appear to be absent 

 in this species and danger thus can not be so well avoided. After arti- 

 ficial removal of the head recrescence takes place inside the tube, in 

 aquaria, with little lapse of time. 



The young are sometimes taken in the tow net in July, the larger ones, 

 8 millimetres long, probably floating upon seaweeds, etc. 



The adult is common upon the quieter, more muddy parts of Bird 

 Shoal and near Crab Point, etc., between tides. 



Diopatra magna, sp. nov. 



(Plate XIV, Figs. 14-20.) 



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

 turned upward so that the mouth is terminal; buccal somite small, 

 ■widened at sides, as narrow above as first setigerous somite, bearing at 

 middle of each side a smooth tentacular cirrus as long as first two se- 

 tigerous somites. Head withdrawn into buccal somite; palps large, 

 globose, with nodules anteriorly ; antennre smooth, with short annulated 

 bases about as long as first setigerous somite ; median anteunie and 

 middle ones four times length of tentacular cirri, outer one about 

 half the length of the median ; tentacles cylindrical, with conical tips 

 as long as bases of autennte. Anterior five parapodia very stout, three 

 upper ones directed forward. Branchiae pectinate, beginning on the 

 sixth setigerous somite as simple filaments. The number of their jiin- 

 nules has increased to about twelve on the thirtieth segment, where 

 the branchine meet on the back. Behind the middle of the body the 

 pinnules of the branchia? decrease gradually in number, the branchiae 

 becoming flabellate, bifid, and finally simply filiform on the posterior 

 somites. Seta? in first five parapodia about thirteen to each, imper- 

 fectly jointed, with the hooked tips and tooth below them inclosed in a 

 delicate hood; other parapodia bear about thirty simple pointed setre, 

 two stout hooked seta3, and delicate, asymmetrical, finely serrated chisel- 

 shaped seta.'. Jaw pieces dark ; lower jaws with whitish tips indented 

 on the edge ; dental i)lates with eight teeth on right and seven on left ; 

 large pair of paragnaths with eight teeth on right and six on left ; un- 

 paired piece on left with eight teeth ; two small pairs of i)aragnaths, 



