Gatty Marine Laboratory, St. Andrews. 17 1 



character to the crown. Such occur in the young as well as 

 in the adults from both places. 



The third or inner row has another modification, the tip 

 leaving the thin shaft at an angle greater than a right angle, 

 and resembling a long foot with a pointed toe, the resem- 

 blance being the closer siuce the heel and foot have a 

 different axis from the shaft. The shaft is proportionally 

 the most slender, and the bending of the tip backwards 

 causes the heel (anterior projection) to stand out promi- 

 nently. Bold transverse striae occur on the face between 

 the ridges, so as to make a rasp-like surface to which mud 

 adheres. Finer stria? are found on the heel and on the tip 

 apart from the ridges. These bristles form a spiny guard to 

 the oral aperture, and are often covered with muddy debris. 

 The crown is supported on a firm fleshy pillar, slightly 

 bifid dorsally, and more distinctly so ventrally, its surface 

 dorsally and laterally being variegated with purplish or madder 

 brown — often arranged in bands dorsally and at the sides 

 of the tentacles ventrally. A circle of acute taperiug 

 papillae pointing forward surrounds the base of the crown, 

 and a brown pigment-band pas;es from the sides ventrally 

 to the lissure. 



Amidst the paleae of two specimens from Southport are 

 numerous examples of a parasite akin to Udonella. 



In the Scottish forms variations in the length of the tips 

 of the second row of palese are not uncommon, two or 

 more of these on each side occasionally forming conspicuous 

 golden curved needles which project far beyond the others. 

 A curious variety was found in its tube attached to Celle- 

 pora off St. Peter Port, Guernsey, in which the external 

 paleoe had the distal central process reduced, so that at most 

 it is only bifid or rarely trifid. The blade is short and 

 broad. The bill-hook series of the second row is also 

 broader and shorter than normal, but the inner paleae (third 

 series) do not materially differ. This form shows that the 

 palese are hollow, formed of two thin plates of a somewhat 

 brittle chitiuoid substance. 



On separating the lobes of the crown the mouth opens 

 in the centre, and it is marked by the same madder-brown 

 pigment, sometimes showing longitudinal stripes on its 

 dorsal edge. It forms a large antero-posterior opening 

 ventrally, the extended sides of which bear six series of 

 purplish tentacles, whilst posteriorly a deep groove lies be- 

 tween a smooth fold on each side. Each series of tentacles 

 springs from a base, as it' formed of a transversely folded 

 sheet of; tissue on eaeh side, the purplish-brown pigment 



12* 



