CuurcH: THE BULB IN CooPERIA DRUMMONDII 341 
too warm at first. A few changes of the water to warmer or 
reheating of the water by placing the container in another vessel 
of warmer water will be found useful. 
MATURE EMBRYO 
The structure of the mature embryo as seen in relief exhibits a 
scarcely protruding pocket, which protects the leaf-primordium 
and the vegetative point by surrounding their outer surface as 
they lie against the base of the cotyledon. The sheath-like base 
of the cotyledon has no vascular system and is very simple in 
structure. The long spindle-shaped cotyledon is succulent and 
projects into the mass of endosperm, absorbing food for the de- 
veloping embryo by means of a layer of thin-walled parencyhma- 
tous cells running parallel with the longitudinal axis of the embryo. 
The suspensor, which is composed of either one or two cells, still 
holds the embryo in position at maturity. 
The number and size of the leaf-primordia, developed at the 
time the seed is ripe, are not at all constant but depend on the 
individual embryo. No cases have been noted, however, where 
the first leaf-primordium had not made its appearance at this 
period. The primary root is protected by a well-developed root 
cap even as early as the maturity of the seed. 
Wordsell (35) has recently given to botany a comprehensive 
paper on the monocotyledonous embryo, where extensive dis- 
cussions and a bibliography relating to the cotyledon may be 
found. His opinion is exactly that of Celakovsky, namely, that 
the cotyledon is an equivalent of the capsule of the moss sporo- 
gonium, just as the hypocotyl is of the seta. Goebel (8) states in 
regard to the cotyledon of the seed plants: ‘‘I need only say here 
that the cotyledons, which so frequently differ in form from the 
foliage leaves, are merely arrested forms of these, the arrest being 
sometimes permanent, sometimes transient.” Lyon also has con- 
tributed (21) to discussions of the true morphological position of 
the cotyledon. At best a discussion becomes one of terminology 
unless combined with detailed anatomical observations on serial 
sections of embryos at successive ages of development. The 
present writer is inclined to agree with Lyon, stating that as the 
cotyledon of Cooperia Drummondii does not appear to arise as an 
