No. 2.] STOLONIZATION IN AUTOLYTUS VARIANS. 27 1 



unfavorable contractions. Very dilute solutions of methylene 

 blue have been of service in studying some of the chains of 

 living individuals, the stain soon becoming sufficiently deep to 

 be of service without producing any noticeable irritation. 



For sectioning, on account of the small size of the animal, 

 great care is necessary in killing the specimens, so as to avoid 

 contortions and separation of the stolons. Several methods 

 were employed. One was to place the worm in very dilute 

 alcohol (3-5^), and in the course of several hours to gradually 

 increase its strength until the animal has become thoroughly 

 benumbed, after which it was placed into the killing fluid. This 

 method gave good results in many cases, but frequently the 

 process of narcotizing required so much time that the sections 

 were ruined. Another method which gave good results was to 

 plunge the worm into 60^ alcohol, remove at once into fresh 

 sea water, and subsequently add alcohol until it was thoroughly 

 stupefied, after which it was placed into the fixing fluid. The 

 best method for killing the animal extended, whenever other 

 fixing fluids than 70^ alcohol were employed, was found to be 

 by placing it on a slide and drawing off most of the water, then 

 applying a very weak solution of the fluid by means of a small 

 brush and gradually increasing the strength of the fluid. In 

 this way frequently almost perfectly straight chains were 

 obtained. 



A number of fixing fluids were tried. Those which gave the 

 most satisfactory results were Perenyi's fluid, corrosive subli- 

 mate, picro-sulphuric with corrosive, Flemming's stronger and 

 weaker solutions, and yo^jo alcohol, the latter giving for general 

 study uniformly the best results. For staining, borax carmine 

 and haematoxylin were used. 



Description of the Species. 



Two distinct varieties of A. varians, described and named by 

 Verrill (11), may be found among the stems of Parypha, both 

 of which occur in about equal numbers. The larger variety is 

 from 10 to 20 mm. in length, is flesh colored, and, when exam- 

 ined under a medium magnification, may be seen to contain a 



