470 



SCIENCE 



[N. S. Vol. XXXI. No. 795 



closed, bears a conspicuous projecting cylindrical 

 " nipple." Within two days the contracted zone 

 gradually relaxes, the nipple disappears, and the 

 end becomes structurally closed. 



The relatively very small tentacles of Sagartia 

 ludce show similar behavior, but the structural 

 closing is accomplished within six hours. 



Sagartia was kept in a solution of chloretone 

 such that all muscular activity was suspended 

 during eight hours. Tlie initial inbending at a 

 distal cut edge nevertheless took place. But the 

 zone of wall which ordinarily contracts to form 

 the nipple did not contract; no nipple was formed. 

 A steady centripetal movement of uncontracted 

 tissue at the cut edge occurred until within eight 

 hours the out end was structurally closed. 



The temporary nipple, therefore, results from 

 muscular contraction, but the definitive closing 

 depends upon non-muscular activities which effect 

 a spatial readjustment of the tissues near the cut 

 edge. 



The regions of a tentacle which are proximal 

 and distal with reference to a plane of cutting or 

 the point of application of a tactile stimulus differ 

 markedly in their immediate reactions to the cut- 

 ting or the tactile stimulus. The form assumed 

 by a proximal cut end is distinctly different from 

 that of a distal cut end. In these respects the 

 Sagartia tentacle tissues, like those of Oondy- 

 lactis, show a distinct polarity which is not ex- 

 plicable upon the basis of their known structure. 



The Regulation of the Water Content in Regenera- 

 tion: Seegius Moeghus, Harvard University. 

 (Introduced by E. L. Mark.) 

 An examination of the water content at suc- 

 cessive stages of regeneration in a polychjet, 

 Podarke obscura, showed that the percentage of 

 water rises rapidly soon after the operation, 

 reaching a maximum between the first and second 

 weeks, approximately at the time of highest re- 

 generative activity; subsequently it begins to de- 

 cline. In this respect (rise and fall of the per- 

 centage curve of water) regeneration is essentially 

 like embryonic growth. But while in embryonic 

 growth the increase of the percentage of water is 

 due to imbibition of water from the surrounding 

 medium, this, apparently, is not the case in regen- 

 eration. 



The regenerating worms, whether fed or starved, 

 are losing in weight, and three phases of regula- 

 tion of the water content in the organism may be 

 distinguished during the process. At first there is 

 rapid loss in weight, but proportionally more dry 



substance than water is lost, the percentage of 

 water rising. Then follows a period of rather slow 

 diminution in weight, when practically no water 

 is being lost, the content of water attaining its 

 maximum. Lastly, comes a period during which 

 proportionally more water than dry substance is 

 being lost, the percentage of water thus declining. 

 The Behavior and Structure of a New Species of 



Gregarine: R. A. Budington, Oberlin College. 



The form described occurs in the alimentary 

 tract of the barnacle, Balanus ebumeus. It is of 

 the polyeystid plan of structure, and is conspicu- 

 ous for the rapidity and complexity of its move- 

 ments. Prolonged progression in a straight line, 

 flexures and torsion of the body, movements of the 

 protomerite in all planes independently of the 

 rest of the body, are specially noticeable. Dis- 

 turbances in the environment of the animal during 

 its progression do not seem to be accounted for on 

 the basis of either Schewiakoff's secretion theory 

 or Crawley's epicytic undulations. 



The nucleus, both while living and when stained 

 " intra-vitam " and after fixation, shows an aver- 

 age of about five very distinct karyosomes ( " pro- 

 chromosomes ") . Bodies of precisely similar ap- 

 pearance and which react similarly to nuclear 

 stains are present in the protomerite; and since 

 the wall of separation between proto- and deuto- 

 merite is complete, the chromatin content of the 

 former, though not contained within an organized 

 nuclear wall, make it in certain ways essentially 

 a separate cell. 



The Function of the Ear in Cyolostomes : G. H. 



Pabkee, Harvard University. (Presented by 



title.) 



Within recent years evidence has been brought 

 forward to show that killifish, goldfish, squeteague 

 and dogfish can hear. No tests have been made on 

 cyclostomes. As their ears are the most primitive 

 in all the vertebrates, they were tested for hear- 

 ing. Ammocoetes will rest quietly on the padded 

 bottom of a wooden aquarium. When the side of 

 the aquarium is struck by a heavy, swinging pen- 

 dulum, the fish usually responds by a winking 

 movement of the oral hood and by curving the 

 body. After the eighth nerves are cut, these re- 

 sponses are called forth only by a blow three or 

 four times as strong as that necessary to stimu- 

 late the normal animal. When only one nerve is 

 cut, the fish responds in a normal manner. These 

 observations show that the cyclostomes are re- 

 sponsive to sound, not only through the skin, but 

 also through the ear. 



