24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 'J2 



Stems which are usually so entangled with the objects on the sea floor 

 and with the stems of other individuals that they are to all intents 

 and purposes as firmly fixed as are the other stalked types. But the 

 c^matulids, attached by their highly mobile dorsal cirri, are able to 

 detach themselves and move about, though as a rule they remain 

 pretty constantly in one place and rarely change their position except 

 as a result of some unusual stimulation. 



Among the comatulids locomotion is of two types, swimming and 

 crawling; swimming is the more usual, and apparently all littoral 

 comatulids can swim. In swimming the arms of each pair beat the 

 water alternately and at first quite rapidly, as much as lOO times a 

 minute, but the animal soon tires and the longest distance recorded as 

 covered by a swimming comatulid is less than 3 meters. The swim- 

 ming of the feather-stars has been likened to the flitting of small 

 birds in shrubbery as contrasted with sustained flight. 



The young of two species, Dorometra nana and Comanthus parvi- 

 cirra (twice) have been captured while swimming at the surface from 

 ships at anchor or in plankton hauls. 



Crawling is accomplished by a combined pulling and pushing, and 

 in the comasterids the long anterior arms are extended forward and 

 used for pulling while the short and stout posterior arms are used 

 for pushing. The rate of progress has been calculated as 85 mm. a 

 minute, or 5 m. an hour. 



COLOR 



Of all the animals in the sea there are none that exceed in beauty 

 and variety of coloration the shallow water crinoids. Flower-like in 

 form and almost flower-like in the fixity of their habit, they are also 

 flower-like in the variety and distribution of their pigments. But 

 with depth the diversity of hue diminishes so that we find the color 

 range of the species of the deeper water relatively restricted while 

 the individuals themselves, losing the almost universal spottings and 

 bandings of the littoral types, become comparatively plain. 



Though crinoids resemble flowers in the diversity and brilliance of 

 their colors, their color types are quite the reverse of flower-like. In 

 a particolored flower the center or eye is more or less abruptly lighter 

 or darker than the remaining portions, or the petals are longitudinally 

 striped ; cross-banding of the petals is very rare. Among the crinoids 

 particolored specimens are usually cross-banded, regularly or irregu-- 

 larly, and though the tips of the pinnules may be of a dififerent color 

 from that of their bases a true longitudinal striping of the arms is 

 very rare and a conspicuous eye is never developed. 



