THE EFFECTS OF LITHIUM CHLORIDE ON THE FERTILIZED EGGS OF NEREIS LIMBATA

¹ Marine Biological Laboratory, Woods Hole, Mass., and Department of Biology, The Johns Hopkins University

1. The fertilized eggs of Nereis limbata were treated with mixtures of sea water and a 0.54 M stock solution of LiCl, ranging from 2 per cent to 100 per cent for periods of 15 minutes to 36 hours. Treatment was begun 75 minutes after insemination of the eggs, shortly before the appearance of the first cleavage.

2. No exogastrulae were observed. There were a few cases of marked abnormalities in the endodermal components of the trochophores within a very narrow range of treatment (15 per cent for 6, 8 and 10 hours).

3. The main abnormalities observed in the experimental larvae were: Absence of the apical tuft, lengthening of the prototrochal cilia, absence of these cilia in varying degrees, abnormalities in the anal and prototrochal pigments, absence or abnormality of the eye spots, deficiencies in the number of prototrochal cells, atypical seta sacs, abnormalities in the number and position of oil droplets. The degree of abnormality in these cases seemed to be roughly proportional to the severity of treatment.