32 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 72 



At the base of the petals in the flowers are the stamens, while at 

 the bases of the arms in the comatulids are the elongated oral 

 pinnules which are usually bent inward over the sometimes central 

 high anal tube which in many cases looks very much like a pistil. 



The essential part of the plant is the flower ; roots, stem and 

 leaves may be dispensed with in the parasitic types, but the flower 

 must be developed. In the crinoids the great essential is the food- 

 collecting apparatus ; everything else may be reduced to a minimum, 

 but that must remain at an irreducible maximum. In the family 

 Rafflesiacese the whole plant is reduced to nothing but a flower, which 

 may be very large, as much as three feet in diameter; in the coma- 

 tulids the animal is little else than arms and pinnules, and the diameter 

 of the expanded animals in one species is about three feet. 



Since the spermatozoa of the crinoids escape into the sea while the 

 ova remain attached to the pinnules of the female it is evident that in 

 this group conditions exist in a way comparable to those found in 

 wind-pollinated plants, and it is interesting to note that the crinoids 

 possess many scores of entirely separate and distinct gonads arranged 

 in a series along both sides of each arm on the pinnules or at the 

 bases of the pinnules remotely suggesting the arrangement of many 

 wind-pollinated flowers in catkins. 



The ciliation of the crinoid larvae may be compared with the 

 development of the fibers on the seeds of such plants as the cotton, 

 and the development of the long anterior tuft of cilia with the coma 

 on such seeds as those of the milkweed {Asclepias) or fireweed 

 {Epilohium). 



The color of the crinoids has already been discussed, but there are 

 one or two points regarding color which are of interest in this 

 connection. 



Many of the species of Comasteridae are asymmetrical, one or two 

 of the arm clusters being more or less, sometimes very much, shorter 

 than the others, the animal developing a secondary bilateral symmetry 

 from an original pentamerous symmetry. Many flowers also develop 

 a bilateral symmetry from an original pentamerous symmetry, as is 

 well seen in our species of Orchidaceae, Scrophulariacese, Menthacese, 

 etc., and in all intermediate stages comparable to those seen in the 

 Comasteridse, in the Campanulariacese and Solanaceae. Because of the 

 coiled digestive tube the visceral mass in the center of a crinoid never 

 shares the pentamerous symmetry of the rest of the animal, and in 

 the pentapartite flowers the similarly placed ovary, excepting only 

 in the Crassulaceae, is out of harmony with the radial symmetry of the 

 other structures. 



