150 FRANCIS E. LLOYD AND CHARLES S. RIDGWAY 



semi-disorganized condition with no protoplasm visible. With 

 the dissolution of the epidermis, the superficial glandular cells 

 become rounded out (fig. 14) and, it seems probable, now begin to 

 secrete nectar. 



After the cuticle is completely released, there is, according to the 

 above account, little or nothing to be seen of the remains of the radial 

 walls clinging to the cuticle. This circumstance makes it practi- 

 cally impossible, when the gland is viewed merely as a solid object, 

 to infer the manner in which the cuticle has been set free. It is, 

 however, clear, from our preparations, that the case is Entirely 

 different from that of the better known type of gland, already 

 referred to, in which splitting away of the cuticle allows the accu- 

 mulation of the secretion between the cuticle and the otherwise 

 unaffected cell or cells to which it belongs. 



With the advance of secretion there is a gradual disintegration 

 of the glandular cells at the apex of the tissue in this and in the 

 other described species. The uppermost show this first in their 

 collapse, and in the disorganization of their contents. At the 

 same time, there is a large accumulation of calcium oxalate, due, 

 it is probable, to the katabolism of the proteins or sugars. 

 The whole structure finally becomes indurated and shrivels. 



General considerations. It has been repeatedly noticed in all 

 our preparations that those radial walls which are seen on edge 

 in longitudinal sections are always oblique, as if their inner edges 

 had been displaced toward the apex of the gland, as indicated on 

 the left extremity of fig. 13. Either shrinkage of the outer epider- 

 mal membrane, or a slight increase in the volume of the gland, 

 would account for this. The latter appears the more probable, 

 since an accumulation of sugars or other solutes would serve to 

 attract water from the tissue below at the base of the gland, fed 

 by terminals of the vascular system (figs. 1,9). 



A further and very curious feature of these glands, first noted 

 by the junior author, is the behavior of the freed epidermal mem- 

 brane upon dehydration. If a strip of this membrane, attached 

 at one end and lying in water, is irrigated with alcohol, it curls 

 away from the gland, just as do theperidial membranes in the aecia 



