l6 SMITHSONIAN INSTITUTION 



As a result of these facts the bulbous root of Scyphocrinus (Camaro- 

 crinus) may be definitely characterized as follows : 



A rigid, hollow, chambered root, consisting of a large spheroidal bulb with 

 a short projecting collar; a stem base with bifurcating roots resting in and 

 forming a large part of the floor within the collar; and several internal, 

 laterally apposed sacs which abut against the inner side of the bulb wall and 

 open separately to the exterior by large channels located between the collar 

 and the axils of the peripheral root branches; the whole innervated and nour- 

 ished by incorporated nervous and vascular systems. Within the collar are 

 the stem base, its proximal bifurcating roots, and a single floor-like layer of 

 root plates formed by the branching and union of lateral rootlets. The collar 

 and bulb wall consist of single layers of similar plates derived from rootlet 

 systems originating at the ends of the proximal root branches, some turning 

 upward and uniting to form the collar ; others turning downward and similarly 

 uniting to form the bulb; while still others, springing from the root axillaries 

 and laterally coalescing, produce the internal sacs. The neurovascular systems 

 passed downward in the stem through the roots and out into the various rootlet 

 walls, forming a reticulated network of surprising magnitude which innervated 

 and nourished each plate of the root. 



The wall structure as above described, the origin and position of the sacs, 

 and the relation of the collar and floor to the other walls, are illustrated by the 

 generalized figure (text-fig. i), constructed by Mr. Wilson from sectioned and 

 fractured specimens in the collection, by which these details are fully disclosed, 

 and by other figures in connection with it. One of the most instructive of these 

 is text-figure 2, showing a part of the collar in which the plates have separated 

 along the suture lines; the striated joint faces of the plates and the pores for 

 the nerve cords are perfectly visible; and it is interesting to note how the upper 

 or finishing row of plates, being rounded except where in contact with the row 

 below it, resembles a strong root built up of radiately striated, discoid ossicles. 



In connection with the development of the root branches are some further 

 curious facts. S«huchert (op. cit., p. 264) noted that " the stalk is generally 

 placed a little eccentrically to the high, most prominent, or primary root 

 member." This is shown by his figure 43 on the same page; and in that, as 

 well as in figure 44, may be seen a low, rounded cusp near the base of the stem, 

 projecting from a root branch that is decidedly larger than the others. This 

 cusp appears to be the remnant of what was the pointed distal end of the larval 

 stem before its attachment to the sea bottom ; and its position results from the 

 fact that the branching of roots was not symmetrical, but took place at one 

 side because the young stem, too thin and pliant to attach itself at the extreme 

 point, made its lodgment at a curve a little way above, so that the stem at 

 that place was for a short distance recumbent. Thus the terminal point of the 



