STAUROCBPHALUS RUBROVITTATUS. 355 



those of the upper (outer) row, conform to the same type, though variously modified. 

 They are split at the base into two flattened plates which lie on each side of a lingual 

 band, and give attachment to the muscles moving the tooth. The median tooth is 

 powerful, and, in the drawing, is by no means acute, having apparently been in active 

 use. On each side are four smaller teeth, the last being minute and often obscured when 

 in situ. They extend along the ridge in a somewhat intricate manner, the teeth having 

 the longest processes being in front of the middle of the row, whilst the posterior teeth 

 are more compact and their processes smaller. The curve at the tip is also more decided. 

 The last tooth abuts on a long serrated horny band, the crenations or teeth being much 

 larger than those on the corresponding portion of the outer and upper row. 



The outer and upper row has ten or twelve distinctly developed teeth (Plate LXI, 

 fig. 7 b). They also occupy a ridge clasped by the bifid base, each lamella of which is 

 somewhat expanded at the tip. A few anteriorly are small, but they soon show an 

 elongated median tooth which projects into the pharynx like a spine slightly bent 

 toward the tip. About five have the long median process, though several of those 

 succeeding have a tendency to the same condition. These teeth diminish posteriorly, 

 sometimes with an irregular mass or two, and then end in a long bar with a finely 

 denticulated edge. 



This apparatus evidently is of importance in feeding, the more powerful lower row 

 performing the sections, whilst the more slender upper series probably aid in holding or 

 manipulating the morsels, the long horny processes especially being useful in this respect. 



The external rows of rudimentary teeth indicated by Ehlers either were not present 

 or had been overlooked in the dissection. These small teeth form a single row beginning 

 externally rather in front of the middle, and continuing backward to the commencement 

 of the posterior bar, when two rows occur, a shorter inner and a longer outer. 



The mandibles are club- or wedge-shaped, broad in front and tapering to a point 

 posteriorly. The broad anterior border (Plate LXI, fig 7 c) is coarsely crenate at the 

 outer edge, but very finely denticulated on its inner edge anteriorly. The two mandibles 

 project beyond the lower lip in some preparations. 



The alimentary canal contains fragments of Crustacea, sand-grains, spicules of 

 sponges, and other debris. 



The minute first foot presents three pointed lobes, a single pale spine and a group of 

 bristles. Two of the lobes are superior, one bearing the spine, and below it the bristles, 

 which have jointed bifid tips and dilated ends of the shafts with bevelled edges. The 

 other is the ventral cirrus. 



The feet gradually increase in size, so that at the fourth or fifth there is dorsally a 

 thick cirrus, with a conical articulation at the tip (cirrophore and cirrostyle, Pruvot and 

 Racovitza), and internally two slender spines which pass almost to the tip of the organ. 

 Beneath are a trifid setigerous lobe— the pale spine passing between the upper divisions— 

 and also the simple bristles, which are slightly curved toward the somewhat blunt end 

 and finely serrated on the upper or convex edge. Along the lower edge of the furrow of 

 the trifid region is the dense group of the translucent jointed bristles, the shafts having 

 dilated and bevelled ends and bifid terminal pieces. The ventral lobe of this division is 

 broadly lanceolate. 



