244 ILYANTHID.E. 



Disk. Reddish buff ; each radius marked with a minute brown speck 

 in its centre : the gonidial radius, however, and the opposite one, are pure 

 white, without spots. 



Tentacles. Pellucid, each marked with a double row of brown arrow- 

 heads, exactly as P. hastata, but the foot is crossed by a band of deep 

 brown, the discal edge of which is perfectly defined; the confluence of 

 these bands forms a broad circle of brown bounding the disk. In the 

 gonidial tentacle, however, and in the opposite one, the band is wanting, 

 as well as the lower arrows, the opaque white of the radius running up 

 the front of each of these tentacles half-way to the tip. 



Mouth. Dark brown. 



Conchula. Pure opaque white ; the lobes without spot or core. 



Size. 



Length three inches; greatest diameter one inch and a half. Disk 

 three-quarters ; tentacles about one inch. i 



Locality. 

 The Channel Islands. 



I have had no opportunity of seeing the animal to which 

 the above description applies. It was taken at Guernsey, 

 in December, 1858, and came into the possession of Dr. 

 Gr. C. Wallich, who has kindly drawn out for my use 

 copious notes, and furnished me with beautiful coloured 

 drawings. It appears intermediate between hastata and 

 undata, the species already recognised ; but I cannot satis- 

 factorily assign it to either, as it differs from both in the 

 form and number of the conchular lobes. I have there- 

 fore given it a name expressive of these peculiarities. 



" The suctorial processes," remarks Dr. Wallich, " ap- 

 pear to consist of simple depressions of the integument, 

 each of which exhibits an oblong muscular body at its 

 base, whereby a vacuum may be formed, and adhesion 

 accordingly secured. On examining these muscular bodies 

 under a power of 250 diameters, longitudinal as well as 

 transverse striae are distinguished. The nature of these 

 suckers was strikingly manifest on attempting to turn the 

 animal in the glass, when they exhibited the appearance of 



