296 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 7 



A 15-segmented larva, perhaps of this species, was taken in tow on 

 April 28. The prostomium and anterior parts had the proportions shown 

 in pi. 47, fig. 29. From the fourth setiger the alimentary tract was darkly 

 pigmented. Neurotrochs were present on setigers 3, 6, 9, and 10. The 

 pygidium was hemispherical, without cirri, but with well-developed telo- 

 troch. The prototroch was still strong, but the anterior end had long 

 smooth capillaries directed anteriorly and laterally. Tridentate hooded 

 hooks, such as characterize adults, were present in neuropodia from the 

 twelfth segment; segments 1 to 11 had smooth capillary setae only. The 

 general appearance of this larva was reminiscent of another larva seen in 

 the plankton on several occasions; in the latter, however, the anterior 

 bristles were markedly spinous; it is believed to have been that of a 

 Disomidae — a small family nearly related to the Spionidae. 



The latest stage observed in the plankton was a 32-segmented larva, 

 taken on April 25. In general appearance and color pattern it was much 

 like the smaller larvae observed. The first setiger had a ventral fascicle of 

 capillary setae; from segment 17 neuropodia had 2 tridentate hooks 

 between superior and inferior capillary setae. 



Genus SPIOPHANES Grube 



This genus is characterized in lacking branchiae; the frontal margin 

 of the prostomium is usually produced in a pair of laterally directed proc- 

 esses that are continuous with the prostomium or articulate with it. Noto- 

 podia have only long pointed setae; neuropodia, after a number of ante- 

 rior segments, have hooded hooks that are distally bi- or tridentate. Only 

 5 species have been ascribed to it — S. bo?nbyx Claparede, cosmopolitan in 

 distribution; S. cirrata Sars, from cold waters of the Northern Hemi- 

 sphere; S. fi?nbriata Moore, dredged off California; S. kroyeri Grube, re- 

 ported from many seas; and S. malayensis Caullery, from Amboina. 

 S. missionensis, described below, is believed to be new to science. 



Spiophanes missionensis, new species 

 Plate 46, Figs. 17-21 



The general form is minute, slender, total length about 10 to 15 mm, 

 number of segments about 110. The prostomium is longer than broad, 

 with a depressed, laterally produced frontal margin (pi. 46, fig. 17) but 

 not strictly with lateral horns. There are 4 minute eyespots, disposed in 

 trapezoidal arrangement, the anterior pair wider apart and less distinctly 



