No. 646] SHORTER ARTICLES AND DISCUSSION 473 



strained through three thicknesses of bolting silk of very fine 

 mesh. As the larva add segments more food is given. When the 

 larvffi build their tubes both food and mud are added until the 

 bottom of the dish is well covered. The method of preparing the 

 diatom culture may now be considered. 



In 1911 I procured food according to the method described by 

 Hempelmann in his study of the life history of Nereis dumenlii 

 at Naples. This method consists principally in scraping the 

 growths from the live tables. The bottom and sides of ac^iaria 

 under running sea-water fn^iuently show a felt-like growth of 



of both Nereis limhata and Platyxnris. The method does not 

 allow the rearing of any large number of worms. Similarly, at- 

 tempts at a pure culture of diatoms gave poor results. 



In 1913 through the kindness of Dr. (^aswell Grave I procured 

 a remarkably fine culture of diatoms from Beaufort, N. C. With 

 this, the firs't sexually mature worms were obtained. But obvi- 

 ously, Plntynerei^ at Wood.s Hole must live on food got in Woodr, 

 Hole waters. I, therefore, made various attempts to get an ade- 

 quate diatom culture from the imm(>(liate vicinity. The success- 



ful metlK 

 At the 



oni Kc 



For voun'>- worms a suspension of diatoms strained through 

 severarthicknesse. of bolting silk is used. The diatoms for this 

 purpose are previ(msl^ exaniino.l under the niicniM-ope. one c.c. 



