216 PROCEEDINGS OF THE ACADEMY OF [Vol. LXXV 



Remaining thoracic somites gradually increase in length, with 

 little change in diameter. They are smooth and quite undefined 

 above and indicated below chiefly by glandular plates which become 

 successively smaller and thinner until on the last two or three they 

 have almost disappeared. About twenty much softened abdominal 

 segments remain. They are fairly well indicated by furrows and 

 the anterior are longer than wide but the proportions gradually 

 alter until the posterior are twice as wide as long. 



Definite parapodia begin on VII; dorsal setae fascicles and tuber- 

 cles small (especially the first) but increase in size for several 

 segments, flattened and directed obliquely dorsad. Tori very 

 small, flattened processes immediately beneath the setae tufts, 

 diminishing in size posteriorly where they are scarcely visible 

 on many segments. Abdominal tori are even smaller and the dorsal 

 cirri appear to be totally lacking. 



Nuchal spines absent. Setae of fascicles IV- VI in short, vertical, 

 slightly curved lines of thirty to forty each, the stems deeply 

 buried, the blades very short, delicate, tapered to acute points and 

 the dorsalmost just visible above the dorsal level of the segments. 

 Fascicles of succeeding segments flattened and consisting of pairs 

 of large and small, normally bilimbate acute setae, there being 

 only six pairs on VII and these much larger than the setae on IV- 

 VI but smaller than those on succeeding somites, which usually 

 bear eight or nine pairs. 



Uncini small and of moderate number, about fifty on X, falling 

 to eighteen on XXV. Thoracic uncini (Plate XVIII, fig. 28) are like 

 those of Melinna in outline and bear two series of closely appressed 

 teeth of three and four or four and four each. Abdominal uncini (fig. 

 29) resemble those of Terebellides, have broad crowns with teeth 

 arranged in four rows of 1, 4, 6 or 7 and 10-12 respectively, the 

 size of the teeth decreasing as their number increases. 



Station 4396, off Santa Catalina Islands, lat. 33° 01' 35" N., 

 long. 121° 32' W., 2228 fathoms, red mud. Type only. 



AMPHICTENIDAE 

 Pectinaria brevicoma Johnson. 



A large number of specimens agree with Johnson's description. 

 The smaller scapha spines are, however, somewhat more stronglj^ 

 hooked, and Johnson 's figures of the uncini do not show the enlarged 

 base or manubrium. Paleoli vary in number with the size of the 

 worm from eleven to fourteen pairs and on full-grown specimens 

 the paleolar membrane bears about thirty-two marginal cirri. 



Numerous tubes are formed of sand grains, sometimes fine, 

 sometimes coarse and of various colors, but occasionally in part 



