296 ANNELIDA POLYCH^TA ANDREWS. 



bearing a broad, spreading lamella, wliich projects most at the ventral 

 posterior part and is not prolonged anteriorly. Anus terminal some- 

 what below the axis of the body and the center of the area circum- 

 scribed by the Hange or lamella. All except buccal and anal somites 

 bear dorsally a fascicle of slender seta? ; 4 to 5 long bilirabate ones, and a 

 greater number of more hair-like slender ones; a few middle somites 

 bear also a few very long undulating setie, serrulate, with delicate 

 lamelhe. The tirst three setigerous somites bear ventrally each a single 

 stout, amber-colored spine, which is bluntly pointed, transversely 

 striate below, and projects plainly beyond the cuticle. 



The other setigerous somites bear a single row of uncini, about ten 

 in the fourth setigerous somite and twenty in the posterior ones; each 

 has five teeth and a single stout bristle crossing over the main tooth. 

 Length up to 100 millimetres, diameter 3 millimetres. Color variable, 

 brown, flesh-color, dark red ; fourth to ninth somites often darker. 



This Annelid constructs thick, coarse tubes of sand, often cemented 

 together in groups and soiled and convoluted a few inches below the 

 surface of the sand, forming thus firm clumps into which the Annelid 

 retreats and from which entire individuals can be taken only with difli- 

 culty, as the body breaks with the tube. Parts at least of many indi- 

 viduals are thus protected from storms and other destructive agents. 

 Many are found with newly-formed heads or posterior ends. This is a 

 common form on the outer edge of Bird Sboaland is sometimes exposed 

 at very low tides, living in sand mingled with shells or fragments. 



Family AMMOCHARID.E. 



AMMOCHARES Grube. 

 Ammochares aedificator, sp. nov. 



(Plate XIV, Figs. 42-45.) 



Body cylindrical, smooth, tapering posteriorly, divided by bands of 

 uncini into eighteen to twenty-one sections, the first six very long, sub- 

 equal, forming about two-thirds of the entire length, following sections 

 rai)idly becoming very short. Body terminates posteriorly, simply, 

 conically with slit-like anus ; anteriorly in crown of tentacles surrounded 

 by a delicate membranous collar. The tentacles present five chief 

 fleshy stems on each side, branch four times, generally dichotomously, 

 and end in blunt lobules; dorsally they are separated by a median, 

 slightly triangular lobe and ventrally by an interval. Mouth terminal 

 with three fleshy lobes or lips, one dorsal, two lateral. First section of 

 the body bears two fascicles of set.T on each side; the posterior one is 

 near the middle of the section and contains about one hundred seta'; the 

 anterior one is halfway between the posterior and the tentacles and con- 

 tains fewer seta?. There is, moreover, a small fascicle of about twenty setae 

 nearer the dorsal line and quite near the posterior end of the section 



