Langdon, Sense- Organs of Nereis lirens. 3 



A peculiar form of epidermal cell has been incidentally- 

 noted. This cell apparently serves as an anchoring cell for the 

 peripheral ends of muscles. 



II. Methods. 



My material was obtained along the southeastern coast of New- 

 England ; it was used in part at once and in part after shipment to Ann 

 Arbor. It was found that the worms which were simply left in the 

 open jar of sand and sea weed in which they had been shipped kept 

 better than those which were placed in artificial sea water. The sand 

 and sea-weed were kept loosely packed and the water lost by evapora- 

 tion was replaced by distilled water. 



Alcohol used as a kiUing fluid rendered the cuticula so resistent as 

 to interfere with sectioning, but Miiller's fluid without the use of an- 

 aesthetics gave very good results. When this fluid was used, the cu- 

 ticula did not become resistent, the tissues stained readily afterward, 

 and the epidermal structures were very well preserved. Paraffin sec- 

 tions were cut 10 fi thick and mounted by Pringle's variation of the 

 hot water method as given by Lee. I find if my slide is chemically 

 clean, the sections perfectly straightened, and then allowed to dry fully 

 24 hours before further manipulation, there is not the slightest need of 

 any fixative with this process. The slides may be carried through a 

 complicated process afterward without losing a section. Kleinenberg's 

 hsematoxylin gave the best results for general work and for a study of 

 the spiral organs. The Biondi-Ehrhch three color mixture, hthum car- 

 mine followed by Lyons blue, and Licht-griin followed by orange G 

 were useful for differentiating glandular tissues. 



For special nerve stains, both the silver nitrate and the methylene 

 blue were tried ; the silver nitrate proved so difficult and the methyl- 

 ene blue so easy that finally the latter was used exclusively. The 

 method used was in general that given by Bethe ('95). It was found 

 absolutely necessary that the circulation of the worm should be vigor- 

 ous at the time of mjection ; in this case the blood-vessels would be 

 filled with the blue and the nerve tissues well stained; but if the circu- 

 lation were feeble at the time of injection, the blood-vessels would be 

 found to be filled with clotted blood and but little if any of the nerve- 

 tissue would be stained. 



My best results were obtained as follows: Vigorous worms were 

 injected with i^^ % Ehrlich's methylene blue in normal salt solution. 

 The injection was made into the body cavity of the worm, care being 

 taken not to inject enough in any one place to cause much sv/elling. The 



