190 ITS APPEARANCE 



of alarm, real or supposed, it will suddenly close, and 

 assume a distended globose appearance, with the oval 

 mouth a little open, and fiUed with the clustering 

 tentacles. 



In colour the variety, though considerable, is re- 

 stricted to certain limits easily defined. The most 

 beautiful varieties that I have seen are the pure white, 

 and the rich full orange or red-lead ; but the more 

 common states are cream-colour, flesh-colour, pale 

 red, and oUve. This last is perhaps the least pleasing 

 hue, but there is considerable variation even here, for 

 in some the tint approaches to a warm umber-brown, 

 and in others becomes a dingy blackish olive. Ge- 

 nerally speaking, the hue, whatever it be, is uniform 

 in the same individual ; but I possess specimens, of 

 the umber-colour, in which the tentacles are almost 

 white, imparting a peculiar speckled aspect to the 

 disk ; the crenated mouth in these is full orange.* 



The body is smooth, lubricated with mucus, and 

 perfectly free from sucking glands. It forms at the 

 summit of the column a thick rounded rim, sometimes 

 everted, not in the least crenated, within which a deep 

 groove exists around the exterior of the tentacular 

 disk. The latter is membranous, expanded, and ex- 

 cessively puckered or frilled with broad and deep 

 involutions, of which there are usually six or eight';" 

 the infoldings are sometimes simple, sometimes com- 

 pound; in the latter case forming a semi-globose 



• The specimen described in the Cornish Fauna (iii. 79,) referred to 

 by Dr. Johnston as probably belonging to another species, I should 

 suppose to be but a variety similar to the abore. The only thing- 

 remarkable in it that I see is, that it is said to live " between tide- 

 marks." 



