1909.] NATURAL SCIENCES OF PHILADELPHIA. 255 



for most of the length of both dorsal and ventral faces. No eyes or 

 nuchal organs visible. 



Peristomium a simple ring, strictly terete and about one-half as 

 long as and slightly wider than the prostomium; its free ventral border 

 forming a furrowed lip bounding the large mouth. 



Somite II also achsetous, slightly smaller and more strongly convex 

 laterally, in the latter respect resembling the setigerous segments. 

 Body terete or with the venter slightly flattened, a little wider than 

 deep and with a more or less evident longitudinal parapodial furrow 

 along the sides. It is slightly enlarged in the middle and tapers gently 

 both ways, the posterior end being more slender. Setigerous segments 

 simple or when contracted faintly triannulate; anterior segments 

 one-third as long as wide, middle and posterior often as long as wide. 

 Pygidium a simple ring with vertical slit-like anus and no trace of cirri. 



Parapodia (PI. VIII, fig. 21) strictly lateral, minute, the posterior 

 ones slightly larger but never exceeding one-third the length of their 

 somites; all similar, consisting of a small rounded setigerous tubercle 

 and a small postsetal lobe slightly flattened and bent dorsad. 



Seta? few, varying from nine to eleven anteriorly and six or seven 

 posteriorly; all pale yellow and of one form (PI. VIII, fig. 22), some- 

 what geniculate, with the narrowly limbate end exhibiting a gentle 

 sigmoid curve. In the bundles they tend to separate into a dorsal 

 and a ventral group, the former including the somewhat larger number, 

 or into three groups, the dorsalmost of which is formed of one, two or 

 three setse having somewhat more prolonged tips than the others. 

 Anterior parapodia are supported by one or two stout acicula com- 

 pletely concealed within the body walls. At about XXV to XXX 

 the aciculum (or acicula) reaches the surface and projects as a stout 

 spine (or 2) ventral to the fascicle of setse (fig. 21), a condition that 

 continues to the caudal end. When two acicula are present one is 

 usually stouter and is accompanied by a minute delicate seta, probably 

 the tip of an undeveloped ordinary seta. 



Jaws when at rest and retracted in somites VIII to X. Although 

 the pharynx is lined throughout by a thick cuticle there is no trace of 

 mandibles in the two specimens dissected. Maxilla? (PI. VIII, fig. 23) 

 black, dense and very hard; the forceps jaws (I) broad at base, stout, 

 very strongly hooked at the end and lacking basal masticatory teeth ; 

 their paired filamentous carriers twice as long as the entire series of 

 jaws and distinct nearly to the anterior end, where they unite into a 

 small vertical plate bearing on its ventral margin an irregular hori- 

 zontal plate with ragged tendons for muscular attachment. Second 



