ON THE DEVELOPMENT OF PARASITIC COPEPODS. 39 



many points on which my material was scanty and to add some 

 new ones. 



I am indebted to Dr. Conklin for constant guidance and assis- 

 tance besides the general direction of my work, and to Mr. 

 Kribs for the use of Zeiss apochromatic lenses. 



Dr. Formad and Dr. Fischelis rendered me invaluable service 

 in translating Russian. 



I am under obligations to the Carnegie Institute for a table in 

 the Marine Biological Laboratory, Wood's Hole, 1904, and to 

 the U. S. Fish Commission for a table in the U. S. F. C. Labora- 

 tory, Wood's Hole, Mass., 1905-6. 



The material was fixed in Flemming's fluid, picro-acetic, or cor- 

 rosive-sublimate-acetic. The first gave the best fixation but the 

 second was the most convenient. Heidenhain's iron haematoxylin 

 followed by various counter-stains, and Hermann's safranin- 

 gentian violet were used most frequently. 



II. HISTORICAL. 



The ground covered in this paper was almost entirely un- 

 touched by earlier workers as regards the particular genera treated, 

 and I will consider here only some papers on related forms. 



The free living copepods have long been favorite objects 

 for study. Gruber ('79) described their reproductive organs. 

 Weismann and Ischikavva ('88 a, b] and Ischikawa ('92) used 

 them in studying the question of reduction in number of chromo- 

 somes. Haecker ('91, '92 a, b, '94 a, b, '95 a, b, '97, '02) found 

 them favorable objects for study of oogenesis, maturation, reduc- 

 tion, and unsymmetrical mitoses. Later, Ruckert ('94, '95 a, b, 

 c) studied oogenesis, maturation, and reduction in these. 



Of the parasitic and half parasitic copepods, Heider ('79) notes 

 the spermatogenesis of Lernantkropus, and Giesbrecht ('82) the 

 oogenesis of the Notodelphidae. 



Charles Branch Wilson in his monograph on the Caligidae 

 ('05) describes the anatomy of the reproductive organs and the life 

 history. 



III. ANATOMY OF THE REPRODUCTIVE ORGANS. 



In Paiuiants, Caligns and allied forms the two ovaries lie in 

 the head (Fig. i) and the two oviducts run backwards to the 



