54 LAGIS KORENT. 



become finer, then indistinct, and finally leave the delicate hair-like tip smooth. The 

 shafts of all are striated longitudinally, and are also crossed at intervals by transverse bars, 

 which, however, do not affect the outline. In the first tuft of bristles the two kinds are 

 more nearly of equal length, and in the last tuft the tips of the simple forms are more 

 gently tapered as well as often fractured, whilst the great length and tenuity of the tips 

 of the second type cause them almost to equal the length of the stronger. In transverse 

 section these bristles are rounded (not circular). 



The hooks (Plate CXXIV, fig. 3 a) have a short horizontal shaft, a rounded crown, 

 six teeth along the front edge in lateral view, then a broader part, which at first sight 

 looks like a seventh tooth, but which really is a series of more minute teeth, as in the 

 typical Pectinaria helgica; finally, the keel below shows a convexity, a hollow, and a small 

 knob at the edge. 



The caudal process recalls the condition in the Opheliidse, just as the head, buccal 

 region and the first body-region do those of the Hermellidse. Two segments without 

 btistles follow the last bristle-tufts, and then a constriction, the anal process sharply 

 curving ventrally thereafter. In outline it is Mysostomum-slmiped, having a convex, 

 obliquely striated ventral surface, and a concave, transversely striated dorsal surface like 

 a sucker, surrounded by a rim, which is notched and papillose, whilst it terminates distally 

 in a differentiated flap ventral to the anus, and another freely moveable flap of the same 

 length dorsally. At the origin of the caudal process three to four hooks (Plate CXXIV, 

 fig. 8 d) occur on each side of the median dorsal groove. They have short, stout, striated 

 shafts and acutely curved tips, a few transverse striae also being present here and there 

 on the shaft, especially at the base. One or two developing forms accompany the former. 

 In a small variety from Norway (dredged by Canon Norman) the dorsal flap has a distinct 

 papillose margin, a condition also seen in those from Naples. 



The anal funnel is, when the animal is removed from the tube, carried at an angle, 

 usually greater than a right angle, to the caudal region, is rounded ventrally, flattened 

 dorsally, and with a spatulate valve hinged dorsally at the tip. The dorsal edges of the 

 process are somewhat scalloped at the base, one deep fissure being present, and each 

 edge has four small clavate papillae. The dorsal surface of the organ is often expanded 

 into a wide sucker with an obliquely ridged centre and a free crenated edge. The 

 apparatus would seem to act as a powerful ejector, and the external parts also, according 

 to Arnold Watson, as an instrument in repairing the tube when broken. He saw both 

 the scapha and its bract at work, " the latter at times apparently pressing down the edge 

 of the material which, mingled with mucus, forms a dome wmich closes in and diminishes 

 the wide opening to a pin-hole " (in lit.). He thought that the internal structure of the 

 scapha suggested a respiratory function. 



Young examples apparently of this form occur frequently in the bottom nets at the 

 end of June and in July in St. Andrews Bay. They occupy little transparent tubes 

 about 1 mm. in length, nearly straight and tapered posteriorly, both ends being open. 

 This areolated tube is composed solely of secretion and mimics the adult's tube of sand- 

 grains; the free edge being formed of somewhat larger spaces, the double edge under 

 pressure being seen to the right. The posterior end of the tube presents a clear, transparent 

 margin, then a granular belt, which is followed by somewhat smaller reticulations than in 



