NO. 7 SEA-LILIES AND FEATHER-STARS CLARK 29 



The coloring matter of crinoids is freely soluble in fresh water and 

 in alcohol. It is possible to keep certain species for some time in 

 water fresh enough to dissolve out a considerable amount of pigment 

 without apparent injury, while many may be partially decolorized in 

 a stream of fresh water while still alive. 



, As a general rule comatulids preserved in alcohol, no matter what 

 their original colors may have been, become brown, usually a yellow- 

 ish, more rarely a purplish, reddish or greenish brown, later slowly 

 fading out to grayish white. The bands and spots often persist for 

 some time, though with entirely changed color values, but they 

 eventually disappear. On account of the wonderful diversity of the 

 colors in life and of the altogether extraordinary alteration of the 

 colors by preservation the greatest care is necessary in identifying 

 living specimens, especially from descriptions based upon preserved 

 material, for the color may or may not be a good specific index ; it 

 usually is not. 



THE SIMILARITY BETWEEN CRINOIDS AND PLANTS 



Although they are animals possessing a relatively high type of 

 organization the crinoids are so plant-like in their outward form that 

 it seems worth while to explain briefly the extent of and the reasons 

 for this curious and striking similarity. 



The roots of the stalked crinoids are of several different types 

 varying from a large encrusting mass with digitiform processes about 

 its borders to -a long slender taproot buried in the mud from which 

 very numerous delicate lateral roots are given off. Every type of 

 crinoid root can be matched among the plants, though the crinoid root 

 performs only one of the functions of the plant root, and that is to 

 hold the organism in place. 



The stem of some of the stalked crinoids, such as Proisocrinus, is 

 long, smooth, slender, and enlarged toward the base, and thus 

 strikingly similar to the stems of many of the commonest palms, this 

 similarity being heightened by the numerous pinnate arms like palm 

 leaves at the summit. The pentacrinite stems with their whorls of 

 five cirri at regular intervals call to mind the stems of many plants 

 with narrow whorled leaves, in combination with their lily-like crowns, 

 especially such lilies as Lilium philadelphicum. From their resem- 

 blance to palms the stalked crinoids are commonly called " sea-palms " 

 in French and Spanish, while their usual appellation in English is 

 " sea-lilies." 



The food of the crinoids consists of the minute plankton organisms 

 suspended or moving slowly about in the surrounding water. In 



