364 O. C. Glaser and C. M. Sparrow 



Isolation of individual capsules, whenever desirable, was accom- 

 plished by means of a capillary tube filled with a suspension of 

 nematocysts. By spreading, from the mouth of such a tube, 

 small drops on a glass slide the nematocysts may be distributed 

 so that each drop contains only a few, or perhaps only one. The 

 drops can then be numbered, and the history of the individual 

 nematocysts followed for any desired length of time. A moist 

 chamber was frequently used to prevent the drops from drying. 



EXPERIMENTS WITH MONTAGUA 



The nematocysts of Montagua are derived from its prey, Tu- 

 bularia crocea. The details in this transfer, are being reserved for 

 another paper. For the present purpose it is necessary to know 

 only that these derived nematocysts are stored by certain entoder- 

 mal cells, the cnidophages, inside the cnidophores of the dorsal 

 cerata, and that when each storage cell has engulfed a certain 

 number it loses its cellular characters and becomes converted, 

 possibly with the assistance of certain neighboring interstitial cells, 

 into a thin transparent bag, the cnidocyst. These loaded cnido- 

 cysts lose their connection with the basement membrane to which 

 in earlier stages they are attached, and come to lie free in the lumen 

 of the cnidophore in the distal end of the appendage. 



Under certain circumstances the elimination of cnidocysts filled 

 with stinging capsules may be observed under the microscope. 

 If the animal is stimulated mechanically, chemically, or best of all 

 thermally, the extrusion of the cnidocysts takes place. They are 

 shot out of the cnidopores at the tips of the dorsal cerata, not by 

 violent contractions on the part of these appendages, but by unob- 

 servable contractions probably of the musculature of the cnido- 

 phore. Relaxation of this musculature immediately around the 

 cnidopore is either incomplete, or if complete, is not great enough 

 to allow the easy passage of the cnidocysts. These, while elimi- 

 nation is going on, are often much distorted, but as soon as the 

 pressure from the walls of the cnidopore is relieved, they become 

 spherical. At times they make their appearance as clear bubbles 

 blown by the cnidopore, and they may remain in this condition 



