132 
naturally be all of approximately the same age, and hence of the 
same size. From natural inference, then, we should suppose that 
young Uintacrinus would not occur with the adults, and also that 
young swarms Would be found in which the individuals were all 
of practically the same size. Such few small specimens as do occur 
with the large ones may be dwarfed individuals, or they may be 
young which have happened to rise to the surface just as the adult 
swarm was passing over. 
Since I published my observations dealing with the coloration 
of the recent crinoids, Mr. Owen Bryant hås brought forth 
evidence to show that insects, especially moths (Noctuidæ) are 
attracted by the violet waves of the spectrum rather than by the 
others, and essentially this same thing has been shown many times 
in the case of marine organisms. This has an especially interesting 
bearing; for littoral and sub-littoral crinoids are largely purple 
or violet, and it may well be that the purple or violet in their 
coloration attracts small organisms to them to a greater degree 
than would colours of other wave lengths. 
Observations made upon a new species of Colobometra, C. 
vepretum, from Singapore, appear to have solved the question of 
the origin of side and covering plates, and to show that they belong 
to the primary and not to the perisomie skeletal series. In this 
species the ventro-lateral margin of the pinnule joints is produced 
into thin flangelike plates of a rounded-triangular shape, the apex 
being opposite the distal end of the pinnule joint. When large, 
these plates tend to break off from the parent pinnule joints and 
form well developed side plates. In certain genera such as Coma- 
tilia and Nemaster in the Comasteridæ, the development is never 
carried any further; side plates only are present; but usually the 
énlarged distal portion of the produced ventro-lateral edges of the 
pinnulars as seen in Coløbometra separates off from the remainder, 
forming a rounded covering plate distinct from the parent side 
plate... This process of separation of the covering plates from the 
side plates is well illustrated in Heliometra glacialis"), where the 
1) ,,Antedon eschrichtii auctorum. 
