6 KANSAS UNIVERSITY SCIENCE BULLETIN. 



tissues. They are destitute of assimilating cell organs, the 

 chromatophores or chlorophyll granules. The outermost lay- 

 ers are composed of smaller cells, nearly isodiametric, which 

 contain the chromatophores and are consequently the assim- 

 ilating tissues." This led the writer to question the effect of 

 these masses of eggs on the meristem region ; could they cut 

 off light enough to interfere with growth or enough to 

 weaken the cells to the point that the fronds would drop off 

 at that point? 4 A large number of observations were made 

 off the east side of Brown Island, several plants which had 

 most of the meristem region covered by egg clusters being 

 under observation for over three weeks. No change could be 

 discerned and the fronds seemed as tough at the close of the 

 period as at the beginning. Professor Rigg's 5 statement that 

 "the region of elongation in this plant extends over the pneu- 

 matocyst and the bases of the fronds" has since come to no- 

 tice and explains the failure to get results. The egg masses 

 were over the bases of the fronds and the top only of the pneu- 

 matocysts, leaving most of the "region of elongation" exposed. 

 At the same time as the above, observations were made to 

 determine the effect of the scorings made when the snails fed. 

 (Fig. 4.) Three healthy plants were selected and tagged. 

 The cuticle was scraped with a knife blade from one side of 

 the base of one cluster of the fronds of the first, from one 

 side of both clusters of the second, and from both sides of 

 both clusters of the third. A fourth was freshly snail-eaten 

 at the same point, the animal having been brushed off in order 

 to see the extent of the damage. These four plants and others 

 were under observation for a month. The cuts did not seem 

 to weaken the fronds in the least. No breaks came and they 

 were healthy until the snails ate them up, that is, peeled so 

 much off in large spots that the fronds were weakened and 

 broke off in fragments. (Fig. 5.) The failure to get positive 

 results from the experiments and from the observations of the 

 snail's feeding habits with this one point in mind nevertheless 

 gave positive evidence as to the loss of fronds in some plants. 

 On the thick beds where the snails were abundant, they ate 

 the fronds in holes, weakening them so that they broke off 

 in large pieces. The snails seemed to retreat before the im- 



4. Since t lie above was written, Doctor Wiley has suggested that the interference with 



- ;| - s exchange by the excretions of the snails might be of more importance than this 



interference witli light relations. 



5. Professor liigg, Fertilizer Resources of the U. S., Appendix L. 



