174 Prof. M'Intosh's Notes from the 



branchiae carries a series of spathulate golden bristles 

 arranged in a single line, the first having 7 or 8, the second 

 9, and the third 10. They are generally directed straight 

 outward, though in life the points are directed backward, 

 and have a flattened translucent tip like the blade of a 

 paddle, the upper end of the shaft gradually dilating into 

 the broad blade ; the dilated part, moreover, showing in some 

 short oblique striae on one side — as if a trace of the striae 

 so common in winged forms. Those of the first set have 

 a narrower tip and longer fringes ; the outer fringes, 

 moreover, being split into finer processes on the margin. 

 Those of the third series have broader tips and the brush- 

 like filaments at the extremity are shorter. Each bristle 

 diminishes in size from the tip to the base, and the shaft is 

 striated. Mingled with the foregoing bristles are a few 

 simple forms, the curved slender tapering tips of which with 

 their sparse spikes project from the skin between the stronger 

 forms. If anything, the first series has slightly narrower 

 tips and more slender shafts than the third, which sometimes 

 shows truncated tips from wear. 



A fold, marked by the purple-brown pigment from each of 

 the dorsal setigerous lamella?, continues the segment ventrally 

 and ends in a papilla with a minute tuft of golden bristles, 

 which, although small, have a similar structure to the larger. 

 Tliey are translucent bristles with long shafts deeply inserted 

 in the tissues, the dilatation of the shaft distally being more 

 gradual, whilst the fringes at the tip of the blade pass much 

 more deeply, so that the whole tip forms a more perfect 

 brush. They are also accompanied by the simple spinous 

 bristles, which are considerably shorter, but go more deeply 

 into the tissues. The physiological importance of the two 

 sets of bristles is unknown, but it may be conjectm'ed that 

 the oar-shaped forms, having performed their functions of 

 fashioning the tube, could be slightly retracted, or the 

 slender ones may be slightly protracted, so that both might 

 act in a brush-like manner. The anterior tuft is the largest 

 and the 3rd the smallest ; the opposite condition occurring 

 in the large dorsal bristles. The direction of these bristles 

 is forward and slightly inward, the angle of inclination being 

 thus different from that in the next series. The last (3rd) 

 set shows faint serrations or stria? at the sides just below the 

 flat tip. 



Between the ventral edge of the lamella for the hooks and 

 the ventral bristles in the second (abdominal) region of the 

 body is a small filiform papilla, longest in front and 

 diminishing to a minute process in the caudal region. 



