16 SABELLARIA SPINULOSA. 



golden curved needles which project far beyond the others and so in one from Wales 

 kindly sent by Arnold Watson. Fauvel specially alluded to this variety, which he has 

 courteously termed var. Intoshi in his recent able memoirs on the Poly charts of St. 

 Thomas and those of Madagascar, and he has given figures of the palea3 and hooks 

 (Plate VIII, figs. 50 — 53). His diagnosis is : Palege of the external row of the operculum 

 with large teeth, without the long median process ; palesD of the middle row short, hood- 

 shaped. Other characters as in the type. This author l also describes another variety 

 viz. var. Gravieri, from the same island, in which the outer row of palese corresponds with 

 the foregoing, but those of the inner row are alternately long and short. A curious 

 variety was found in its tube attached to Cellepora off St. Peter Port, Guernsey, in which 

 the external palese 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 palese (third series) do not 

 materially differ. This form shows that the palese are hollow, formed of two thin plates 

 of a somewhat brittle chitinoid 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 between a 

 smooth fold on each side. Each series of tentacles springs from a base, as if formed of a 

 transversely folded sheet of tissue on each side, the purplish-brown pigment penetrating 

 between the folds and rendering them more distinct. The folds are directed obliquely 

 outward and forward, two on the pillars of the crown being more nearly longitudinal 

 than the others, and, besides, a patch of tentacles closely abutting on the fissure lies to 

 the inner side of these. 



In a decomposing example Mr. Watson removed the superficial tissues of the 

 tentacles with a camel's hair brush, leaving " the skeletogenous shaft, which then appeared 

 as a transparent tube enclosing the muscular sheath of the central canal." 



The tentacles are long and nearly cylindrical filaments which in life often twist and 

 wriggle about. When stretched out they become attenuate, and distinct crenations 

 directed toward the tip occur on their ciliated edges, giving the organ a transversely 

 streaked aspect. Each contains two vessels, apparently a single trunk bent upon itself 

 at the tip, the trunks looping together at the bases of the tentacles. The fluid in these 

 vessels is perfectly translucent and free from granules. The matrix of the process is 

 granular and pale (hypodermic), and seems to keep the vessels from undue pressure, yet 

 retaining sufficient elasticity. Muscular fibres, both longitudinal and circular, are also 

 present, but the latter were not distinctly made out. Under a power of 60 diameters the 

 cilia of these organs are often seen to remain perfectly still, projecting from the sides 

 like minute glassy spikes; then they suddenly are adpressed, the points directed toward 

 the tip of the tentacle. Occasionally they are jerked in various ways, some vibrating 

 rapidly a few times and again becoming rigid. In the quiescent condition they bear 

 some resemblance to the spinous ray of a starfish or to some spine-clad stems like 

 Gleditschia. The tip of the tentacle is more opaque than the rest, from its granules and 

 1 ' Arch. Zool. Exper./ t. liv, p. 142, pi. viii, figs. 42 — 49. 



