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STUDIES IN EARTHWORM CHLORAGOGUE. 



WM. J. RICE. 



The dearth of knowledge concerning the physiological signifi- 

 cance of earthworm chloragogue and the opportunity offered for 

 the study of the subject, are the main reasons for the work here 

 presented, which has been carried on under the direction of Pro- 

 fessor James G. Needham. 



I have found only one article having an important bearing on 

 the subject of this paper, one by Thomas Schaeppi, 1 which was 

 found after this research was practically completed. It may be 

 stated that in several respects a marked similarity exists between 

 the chloragogue of Ophelia radiata and that of the earthworm, 

 especially as to color, strong resistance to acid and alkaline rea- 

 gents and the probability that the chloragogue is excretory in 

 function rather than secretory. 



Litmbricus Jicrcnlcus has served for the most part as material for 

 study. As much as was possible of the work was done with 

 freshly collected material. But when, during the winter months, 

 fresh material was not available, worms were used which had 

 been collected in the late fall and, to insure a thrifty condition, 

 preserved alive for winter use under favorable conditions of tem- 

 perature and moisture. The worms were found to thrive best in 

 temperature varying from 40 to 60 F. Extremes of heat were 

 quickly fatal. It was found necessary to exercise care in the 

 amount of moisture furnished, as too much moisture was as hurt- 

 ful as too little. The results obtained from material properly 

 preserved and from freshly collected material were essentially the 

 same. 



The following points are considered : I. Origin and growth of 

 chloragogue ; II. Distribution ; III. Structure ; IV. Function 

 and V. Elimination. 



I. Origin and Groivth. To learn whether the chloragogue, 

 as is generally supposed, is a modification of the peritoneal epi- 

 thelium, a series of worms was prepared beginning with a young 



1 "Das Chloragogen von Ophelia radiata " Jenaische Zeitschrift fur Naturwissen- 

 schaft, 1893, XXVIIL, Neue Folge XXI. 



