1909.] NATURAL SCIENCES OF PHILADELPHIA. 325 



setip appendages differing in form. S. singulisetis Grube, from the 

 Philippines, also belongs to the subgenus Ehlersia, but has only four 

 eyes. 



Pionosyllis typica sp. nov. PL XV, figs. 5-7. 



Form moderately slender, widest in the region of the gizzard, from 

 which it tapei-s regularly to the caudal end. The well-extended and 

 complete type has 96 segments and is 31 mm. long and 1.2 mm. in 

 diameter at XX^'. 



Prostomium small, somewhat sunken into peristomium, about one 

 and two-thirds times as wide as long, the greatest width posterior, 

 the sides and front broadly and regularly rounded. Eyes two pairs, 

 dark brown, small, anterior pair close to lateral border and about 

 midway of length of prostomium; posterior pair little more than one- 

 half diameter of anterior and slightly behind and within them. A 

 pair of faint ridges run from the posterior eyes to the posterior border 

 of the prostomium, nearly completing with the eyes a ^'-shaped figure. 



Palps completely separated to base, bent somewhat ventrad, broadly 

 triangular with rounded angles, about as long as prostomium and 

 basal width about two-thirds length. Median tentacle arising between 

 posterior eyes, about one and one-fourth times as long as prostomiiun 

 and palps, slender and slightly tapered, divided into about twenty- 

 four articles, distinct distally but ol)scure toward the base, not strongly 

 moniliform. Lateral tentacles similar, arising from a slight depression 

 just anterior to anterior eyes, nearly three-fourths as long as median 

 and reaching nearly as far, divided into nineteen f)r twenty joints. 

 Mouth rather large with prominent crenulated lips. 



Peristomium short and partly crowded beneath i)rostomivun, \n\t 

 visible for entire width of dorsum. Tentacular cirri similar to tentacles, 

 the dorsal slightly exceeding median tentacle in length, with about 

 twenty-six joints; tlie ventral somewhat shorter, with twenty joints. 

 Body segments nearly terete, remarkalily regular but separated by 

 shallow, incons])icuous furrows ; excei:)t for a few short anterior ones they 

 arehalf aslongas wideor more. Prom the maximuiu \\\d\\\ at the end of 

 the first fourth they taper regularly to the pygidiuni. which is a small 

 ring and beat's one of a pair of cirri as long as tlie last nine segments 

 and resembling the ])osterior neurocirri in being scarcely articulated. 



Parapodia (PI. X\'. fig. 5) situated at ventral level of body, well 

 separated throughout, slender, rather conspicuous in \'entral view but 

 largely concealed from tlie doi-sum. The neuropodia are slightly com- 

 pressed and taper slightly to the bluntly rounded and rather abrupth' 

 contracted end, which is divided into two small lips se])arated by a 



