l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL.98 



no annulations were observed. The occupants are difficult to extract 

 entire from the slender tubes, but are probably very much shorter 

 than the tubes they occupy. 



Distribution. — Cape Verde Islands ; Torres Strait Settlements ; 

 Galapagos Islands ; Clipperton Island. 



SPIONIDAE 

 POLYDORA TRICUSPA, n. sp. 



Figs. 3, c-k 



Collection. — Station No. 15-38; 1 specimen. 



Length of 30 anterior segments is 5 mm., width 0.6 mm. Colorless 

 except for 3 black eye spots, 2 of which are anterior, at the sides of 

 the prostomium, and an unpaired one more posteriorly, on the prosto- 

 mial ridge. A dark stripe marks the dorsal longitudinal vessel. 



The prostomium is rounded anteriorly, snoutlike, its length about 

 as great as the base of the head is wide at the place where the palpi 

 are inserted. The prostomial caruncle extends posteriorly as a low 

 ridge to the anterior margin of the modified segment. The palpi have 

 been lost. 



Branchiae are present from segment 8 (the second post modified) 

 to segment 25, or 18 pairs. They are cirriform, recurved over the 

 dorsum, slightly overlapping except in the last 3 branchial segments, 

 where they are shorter. 



The second segment (first setigerous) has a dorsal fascicle of 

 lanceolate setae. Segments 3-5 have lanceolate setae in notopodial 

 and neuropodial fascicles. Segment 6 is modified, provided with 2 

 kinds of stout uncini in the dorsal fascicle, and a small fascicle of 

 slender lanceolate setae ventrally. The stout uncini include 4-5 pairs 

 of (1) longer, pointed spines bent at the tip (fig. 3, d), and (2) 

 equally heavy, though somewhat shorter, triple pronged spines, ac- 

 companying the pointed spines (fig. 3, d). On worn spines (figs. 

 3, e-g) the tips are missing. No fine pennoned, companion setae were 

 distinguished. Bifid hooded crotchets are present in neuropodia from 

 the eighth segment. They have a long main fang, nearly at right 

 angles to the main stem, and a distal tooth less than half as large 

 (fig. 3, li). All notopodia have only lanceolate setae. 



This single specimen is of unique interest because of its relation 

 to observations made on planktonic larval forms during March to 

 April, 1938. These studies were carried on at the Scripps Institution 

 of Oceanography at La Jolla, Calif., under the 'sponsorship of Dr. 



