Date on Master's Thesis/Doctoral Dissertation


Document Type

Master's Thesis

Degree Name


Department (Legacy)

Department of Anatomy


Mollusks; Cytology--Technique


Ever since the latter part of the 17th century, when ciliary movement was first observed, the study of ciliated cells has been of great interest to biologists, particularly to physiologists. In 1713 Leeuwenhoek recorded some observations he made on ciliary activity, using his primitive microscope. A knowledge of the structure and function of ciliated cells is also of importance in that branch of medicine pertaining to disorders of the respiratory passages and the movement of the ovum in the uterine tubes. The bivalve molluscs have come to be the classical example for the study of ciliated cells, both because of the convenience of working with them and because their ciliated surfaces are quite extensive, since this group of animals depends largely on ciliary activity for food and respiration. Almost all of the previous investigations have been carried out on higher forms, the filibranchs, pseudolamellibranchs and eulamellibranchs, all of which have highly specialized ciliated cells. This paper is concerned chiefly with a study of the cytology of the cells of the gills of a primitive protobranch , gills which are largely for respiration and not so much for food-collecting. These feather-form gills are small and not so highly specialized as those of the higher bivalves. An attempt will be made to see if the cellular structure is more primitive than in the more specialized forms previously examined, and to discover, if possible, the lines along which specialization has taken place.