NO. 4 HARTMAN : SPIONIDAE FROM CALIFORNIA 297 



visible, the posterior pair dorsal in position. The prostomial ridge extends 

 back to the region between the palpal bases. 



The first segment has well-developed noto- and neuropodia, with long, 

 tapering cirri; the notosetae are entirely smooth, slender, directed for- 

 ward ; the neurosetae include similar, though shorter, capillary setae and 

 a single stout, recurved, pale spine (pi. 46, fig. 21). The second segment 

 resembles the first save that its cirri are a little smaller than others near 

 them but have thick, glandular areas. Neuropodia shift from a lateral to 

 a ventrolateral position between setigers 14 to 16. The first 14 segments 

 have only long, pointed, capillary setae in both rami. These setae are con- 

 tinued throughout in notopodia. From the fifteenth neuropodium, uncini 

 are present, at first few in number, accompanied by capillary setae, but 

 increasing in number posteriorly. They are distally tridentate (pi. 46, 

 fig. 18). 



The first 16 segments are notably more depressed than those follow- 

 ing. From the seventeenth segment a transverse dorsal membrane is 

 present and continued through the rest of the body length. Where best 

 developed it consists of 18 to 20 short, transverse bands of long cilia, 

 the whole forming a trim, straight row across the dorsum, between paired 

 notopodia. Interramal pouches have not been observed, even in individ- 

 uals with large eggs. 



The egg (possibly near maturity) is oblong, approximately 0.12 x 

 0.096 mm, white; its surface appears punctate on account of numerous 

 depressions under the surface membrane (pi. 46, fig. 19). This egg is 

 reminiscent of that of Poecilochaetus serpens, a member of the Disomidae, 

 described by Allen (1904, pp. 79-151). 



The pygidium is a long ring, with dorsal anal opening, a pair of 

 slender cirri inserted dorsolaterally, and a thick, somewhat depressed, 

 unpaired median papilla ventrally (pi. 46, fig. 20). 



S. misstonensis inhabits well-constructed, sand-covered tubes open at 

 both ends, disposed vertically in sandy beaches. It has been collected only 

 at moderately high-tide line, in Mission Bay, near the place where it 

 enters the ocean, on the north side; here it is common just east and south 

 of a metal culvert that empties into the bay. 



S. ?nissionensis differs from other species of Spiophanes in the follow- 

 ing complex of characters : ( 1 ) the prostomium is anteriorly produced but 

 lacks tme horns; (2) it lacks a median antenna on the prostomium; (3) 

 there are no interramal parapodial pouches; (4) the pygidium has long, 

 paired cirri and a thick, ventral papilla. S. fimbriata Moore (1923, p. 



