1923] NATURAL SCIENCES OF PHILADELPHIA 209 



The former are eylindroid with a small dorso-terminal presetal 

 process and project prominently dorso-laterad from a somewhat 

 rugous lateral area. They become longer posteriorly. A small 

 papilla is borne on the middle of the ventral face of the last three 

 and also on VII and VIII, being exceedingly small on the latter. 

 Uncinigerous tori, beginning on MI, increase in size, the last 

 thoracic being fully 50% larger than the first and its margin equal 

 to at least one-third the body width. All are auriculate, with 

 constricted bases and the ventral angle produced, especially on 

 the more caudal parapodia, into a short cirriform process. 



Abdominal parapodia (Plate XVII, fig. 16) consist of shorter and 

 thicker, more fleshy tori, with more elevated bases and shorter un- 

 cinial lines and become reduced in size and more crowded posteriorly. 

 A rugous, somewhat tumid area connects the tori to the short 

 hamate, and clavate dorsal cirri, which represent the reduced bases 

 of the setigerous tubercles. 



From VII to XVII, the setae fascicles are prominent, becoming 

 increasingly so caudad. They arise in half circles open forward 

 and consist of 12-20 pairs of a large and a very small, deep yellow, 

 delicate, tapering and acute, narrowly limbate seta^, the dorsal- 

 most of which are longest and gently curved dorsad, giving to the 

 fascicles a graceful shape. The minute tuft of very small setae 

 on VI projects from the anterior face and barely reaches to the 

 end of the tubercles. 



Uncini are arranged in a single rank on the anterior face of the 

 distal margins of the tori, the number varying proportionately to 

 the length of the margin from about 190 on X to 110 on XVIII, 

 etc. Thoracic uncini (Plate XVIII, fig. 17) are pale yellowish, 

 broadly triangular with prominently projecting inferior angle, a 

 small ligaiiKuit process and five large teeth with sometimes an in- 

 cipient sixth superior one. Abdominal uncini are somewhat smaller 

 with ventral margin more convex but otherwise similar to the 

 thoracic. Teeth on all uncini strictly uniserial. 



Color pale graj', no pigment, the glandular plates more or less 

 yellowish. 



The luimerous specimens are remarkably uniform in size, varying 

 in length from 35 to 45 mm. and in maximum width (exclusive of 

 parapodia) at IX from 4 to 5.5 mm. Thoracic segments 17 (14 

 setigerous), alxlomijial 12. 



A few fraguKuits of mud tu])es are 8-9 nnn. in diameter with 

 thin very fragile walls of fine silt. 



A large species allied to Grubianella Mcintosh, l)ut peculiar in 

 the reduction of the preuncinial setae tufts. 



"Albatross" station 4382, off North Coronado Island, 618-657 

 fathoms, green mud; 4433, off Santa Rosa Island, 243-265 fathoms, 



