1 74 ECHINODERMA TA. PART in. 



coast of Norway were of brilliant hues red, vermilion, 

 white, and yellow. In general, both plants and animals 

 of the lower kinds become of a sickly white when kept 

 in darkness. 



The Stelleridse are male and female, and form fertilized 

 eggs of an orange or red colour. These eggs are first 

 converted into a mass of cells and then into larvae, not 

 radiating symmetrically like their parents, but of a bi- 

 lateral form, the two sides being perfectly alike and 

 bordered by a ciliated fringe nearly throughout their 

 whole length. These two fringes are united by a superior 

 and inferior transverse ciliated band, and between the 

 two the mouth is placed. A stomach, intestine, and vent 

 are formed ; the creatures can provide for themselves, 

 and swim about as independent zooids. A young star- 

 fish is gradually developed by a succession of internal 

 growths, part of the original zooid is retained, and the 

 rest is either thrown off or absorbed ; then the star- 

 fishes having lost the power of swimming, crawl slowly 

 away and acquire their full size. There is great diversity 

 in the external form of the zooids of the different genera, 

 as well as in the portion of them retained in the adult 

 star-fish. 



Fossil star-fishes have a very wide range. They are 

 found among the earliest Silurian organic forms, but 

 they scarcely bear any resemblance to existing genera. 

 The Ophiuridse, fished up from the bottom of the North 

 Atlantic, come nearest to them. Five genera are found 

 in the Oolitic formation, all extinct ; three genera range 

 from the Lias to the present seas ; and five genera be- 

 longing to the Cretaceous period are represented by 

 living species. 



Echinodermata Crino'idea. 



The Crinoid Echinoderms, or Stone-Lilies, are like a 

 tulip or lily on an upright stem, which is firmly fixed 



