Decembke 30, 1898.] 



SCIENCE. 



939 



the spring or pool. It has been supposed 

 that the disappearance of the softer parts 

 of the leaf was due to decay brought on by 

 bacteria and fungi, and this may in some 

 cases be true. 



A few months ago some moss from a pool 

 near the Great Falls of the Potomac was 

 brought into the laboratory of the Division 

 of Vegetable Physiology and Pathology and . 

 put into an aquarium. A few leaves of 

 Norway maple afiected with a spot disease 

 were also put in to keep them fresh for a 

 few days. It was soon noticed that the 

 mesophyll and epidermis of the brown spots 



ress through the water or aid them in 

 crawling. The mandibles and mandibular 

 teeth are stout and well adapted for gnaw- 

 ing. (See Figs. A-D.) An examination of 

 the alimentary canal of several of the or- 

 ganisms revealed the presence of numerous 

 leaf cells, palisade and mesophyll, in the pro- 

 cess of digestion. Little doubt could, there- 

 fore, remain as to the fact that the Cypri- 

 dopsis were the active skeletonizers. 



Another aquarium, however, was started, 

 and decay-producing fungi and bacteria 

 were introduced to see if they would alone 

 produce skeletonizing. 



A. Side view X 50 diam. 



■ / 31 



Fig. 1. CYPEiDOPsis sp. 



B. Natural size. C. Ventral view >( 50 diam. D. Dorsal view X 50 diam. 



was disappearing, leaving nothing but the 

 vascular bundles. A closer examination re- 

 vealed numerous minute bivalve crustaceans 

 belonging to the family Cyprididte and as 

 nearly as could be determined to the genus 

 Cypridopsis, probably G. vidua, (O. F. M.). 

 The shells varied from 1/2 to 1 mm. long 

 and half as broad and high. They are 

 tumid, yellowish green and covered with 

 short hairs. In swimming the plumose an- 

 tennae and bristly feet protrude from the 

 shell and by their rapid movement cause 

 the organisms to make a jerky rolling prog- 



Two sets of leaves of Norway maple, 

 Peach, Eose, Elm, Linden and a number of 

 other plants were selected. One set was put 

 in the aquarium containing the Gypridoims 

 and the other put in the aquarium with 

 fungi and bacteria. The process of decay 

 went on very rapidly in the latter aquarium, 

 but there was no sign of skeletonizing a 

 month and a half after the experiment 

 was started. In the aquarium with Cypri- 

 dopsis, however, the work was begun al- 

 most immediately. The dead spots in the 

 leaves were skeletonized in 24 hours, and 



