JO CHAS. W. HARGITT. 



graphs taken by Dr. Sobotta, by whoso kind permission I am 

 able to present them here. As will be seen, the aspects of the 

 tubes and of the openings through which the creatures protruded 

 their heads are so extremely diversified as to seem to be abso- 

 lutely chaotic. If one may distinguish any tendency toward a 

 given aspect of position, still the departures are so numerous as 

 to render it almost certain that no single factor could have been 

 determinative. As in the case of Hydroides ('09, p. 180. etc.), 

 Pro! nla has left in ii> tubes a convincing record of the erratic 

 individuality of its behavior the significance of which is ex- 

 tremely important. 



Autotomy. In this connection may be considered a feature of 

 behavior more or less unique, though not peculiar to Protula, 

 since it has been noted in several cases of Spirographis] namely, 

 that of autotomy, or the self-excision of certain organs of the 

 body. This was first observed in the case of Protula. A speci- 

 men of this worm was among the first to come under my observa- 

 tion, having come to my table almost the first day in the labora- 

 tory. It had been placed in a small aquarium jar on the table 

 for convenience of study. After finishing a given series of tests 

 the specimen was usually returned to the large aquarium. On 

 January 7 the specimen had been under observation and was 

 Ic-ft in the table jar which had a capacity of about four or five 

 liters, while I went out to lunch. This could hardly have been 

 more than an hour or so, but on ivturn I observed what seemed 

 strange the detached portion of about half of the gill mass lying 

 at the base of the tube. An examination of the gill failed to 

 reveal any signs of disease or other abnormality. My first im- 

 pression was that possibly the water had become "bad," yet 

 other living things, such as copepods, showed no signs of dis- 

 comfort. However the water was renewed several times during 

 the afternoon and the specimen finally left on the table over 

 night, as had been done several times before. The following 

 morning upon examining the jar I lound tin- oilier portion of the 

 gill in I he same detached condition, lying at I lu- base of t he tube, 

 but the specimen was deeply retracted within the tube. After 

 some time it came to the orifice and showed clearly that it was 

 entirely devoid of gill elements. It was now transferred to the 



