24 G- H. Parker 



h. Injury 



The great majority of fingers cut from Stvlotella, if put directly 

 under the microscope, show no ostial currents. As a rule these 

 currents begin to appear in from ten to fifteen minutes after the 

 finger has been cut off. When a finger that has estabhshed its 

 ostial currents is cut in two, these currents often cease in the two 

 parts though sub-dermal and oscular currents can be easil/ demon- 

 strated. After a quarter of an hour the ostial currents can usually 

 be seen again in such pieces. Not all specimens show these con- 

 ditions, but they are of common enough occurrence to justify the 

 conclusion that a considerable incision in Stylotella produces in its 

 neighborhood a temporary closure of the ostia. In this respect the 

 ostia resemble the oscula. 



c. Chemical Stimulation 



To sea water containing ether (§ per cent) or chloroform (^ per 

 cent) the ostia closed even more quickly than the oscula did, and 

 on fingers whose ostia were closed, the presence of ether or chloro- 

 form in the surrounding water did not induce these apertures to 

 open. Strychnine, one part in fifteen thousand of seawater, was 

 followed bv a gradual closing of the ostia, a condition already 

 observed by von Lendenfeld ('89, p. 608) in other sponges. To 

 one part of cocaine in a thousand parts of seawater open ostia 

 closed in about ten minutes and closed ostia remained closed. To 

 one part of cocaine in ten-thousand parts of seawater the ostia 

 remained open or if closed in the beginning, they open in about 

 eight minutes. Of this drug von Lendenfeld ('8q, p. 640) states 

 that the stronger solutions cause a contraction of the ostia, which 

 is true, and that the weaker solutions leave these apertures un- 

 changed, which is probably not wholly correct, for they inhibit 

 to some extent the contractibility of the sphincters. To atropin, 

 onepartina thousand of seawater, the open ostia remained open 

 and the closed ones opened in about nine minutes. Thus atropin 

 probably also inhibits the action of the sphincter. As the actions 

 of these various drugs on the ostial sphincters is very similar to 

 their action on smooth muscle, it is probable that the ostial myo- 



