4 Sea Lilies. 



by no means easily broken, even when dead and dry. They 

 also by their elasticity admit a certain degree of passive 

 motion. There are no muscles between the joints of the stem, 

 so that the animal does not appear to be able to move its stalk 

 at will. It is, probably, only gently waved by the tides and 

 currents, and by the movement of its own arms. In the 

 upper and newer part of the stem five series of strongly- 

 marked pores pass inwards between the stem-joints at the 

 bottom of the five longitudinal grooves. The function of these 

 pores is unknown. 



In G. Caput-Medvsce about every seventeenth joint of the 

 lower, mature part of the stem is a little deeper, or thicker, than 

 the rest, and bears a whorl of five long tendrils, or cirrhi. The 

 stem is, even near the base, slightly pentagonal in section, and 

 it becomes more markedly so towards the head. The cirrhi 

 start from shallow grooves between the projecting angles of the 

 pentagon, so that they are ranged in five straight rows up and 

 down the stem. The cirrhi are made up of about thirty-six to 

 thirty-seven short joints. They start straight out from the 

 stem, rigid and stiff, but at the end usually curve downwards, 

 and the last joint is sharp and claw-like. These tendrils have 

 no true muscles; they have, however, some power of con- 

 tracting round resisting objects which they touch, and there 

 are olten star-fishes and other sea monsters entangled in them. 

 Near the head the cirrhi become shorter and smaller, and 

 their whorls closer. The reason of this is that the stem grows 

 immediately below the head, and the cirrhus-bearing joints 

 only, are formed in this position, the intermediate joints being 

 produced afterwards below each cirrhated joint, which they 

 gradually separate from the one beneath it till their number of 

 seventeen or eighteen is complete. 



At the top of the stem five little calcareous lumps like 

 buttons stand out from the projecting ridges, and upon these, 

 and upon the upper plate of the stem, the cup which holds the 

 true body of the animal is placed. These buttons are of but 

 little moment in this form, but they represent parts which are 

 often developed into large highly ornamented plates in the 

 various tribes of its fossil ancestors. They are called the basal 

 plates of the cup. Next, in an upper tier, we have a row of 

 five oblong plates opposite the grooves of the stem, and all 

 cemented together in a ring. These plates are separate when 

 the animal is yonng. They are called the first radial plates. 

 They are the first of long chains of joints which are continu- 

 ous to the ends of the arms. Immediately above these plates 

 and resting upon them there is a second row of plates nearly of 

 the same size and shape, only they remain separate from one 

 another, never coalescing into a ring. These are tho second 



