1906.] NATURAL SCIENCES OF PHILADELPHIA. 245 



like, ancrmay be arranged spirally (fig, 43a) ; others are very greatly 

 elongated, thread-like, openly spiral, tapered very gently to acute tips, 

 and have the lateral processes reduced to minute appressed scales (fig. 

 36). The latter spring in a group from the ventral side of the bundle. 



Typical crochets (figs. 38 and 39) have rather slender, strongly 

 curved stems with an asymmetrical nodulus near the middle, the head 

 very little enlarged and provided with a stout, rather long, moderately 

 acute, strongly hooked, and slightly recurved rostrum, above which 

 is a prominent crest consisting of five, or sometimes of four, depressed, 

 overlapping, diminishing teeth. There are no lateral teeth, but the 

 striations end in several groups of conspicuous markings just below 

 the principal teeth. The guard arises close beneath the rostrum, but 

 separated from the latter by a distinct space. There is no distinct 

 guard process or shoulder, but the guard arises as a distinct transverse 

 plate, soon becoming divided into about twelve slender, tapering fila- 

 ments, which spread around the end of the rostrum or overarch it. 

 The stem, neck and posterior part of the head are strongly striated. 

 Posteriorly the stems of the uncini increase in length. On somite V 

 all of the uncini have the form shown in fig. 37. The stem is straighter, 

 beak less hooked and the teeth of the crest fewer and more erect. 

 The guard is rudimentary. 



The head and succeeding three or four segments are very smooth, 

 iridescent and of a uniform deep purple or reddish-brown color above, 

 not at all spotted or blotched ; the next three segments are smooth and 

 yellowish throughout; those of the middle region have pale anterior 

 glandular zones, the remaining parts being yellowish and roughened; 

 while posterior segments are pale throughout and thin-walled, except 

 in the position of the longitudinal muscles and glandular zones. 



The tubes are stout, thick-walled, hard but fragile structures, com- 

 posed of fine sand grains, sponge spicules and bits of rock cemented 

 together firmly and lined by a thin mucoid layer. Several tubes are 

 sometimes coherent side by side. 



Fragments of this species occur in the collections from the Gulf of 

 Georgia, Station 4,197, 31 to 90 fathoms, on a bottom of sticky green 

 mud and fine sand, and Station 4,198, 157 to 230 fathoms, on a soft green 

 mud bottom. The type locality is Station 4,227, in the vicinity of 

 Naha Bay, Behm Canal, 62 to 65 fathoms, dark green mud and fine 

 sand. 



Nicomache carinata is easily distinguished from A'^. per sonata John- 

 son by the possession of two achaetous preanal segments, while the 

 latter has but one. In this respect it resembles A'', lumbricales Malmg,, 



