1917] Kofoid-Swezy : On the OrieniaUon of Erythropsis 99 



He furthermore concludes that the transverse flagellum takes its orgin 

 at the region which we interpret as the attachment area. If we orient 

 the body in the usual position the girdle and flagellum would thus 

 form an ascending right spiral instead of a descending left one and the 

 symmetry of these two fundamental structures, the girdle and flag- 

 ellum, would be reversed. 



The grounds upon M^iich this interpretation rests appear to be 

 "logical" rather than observational. There is no evidence in Faure- 

 Fremiet's account that he had correlated his orientation with the loco- 

 motor activities of the animal. He does not state that he has seen it 

 advance prod first and with the ocellus directed posteriorly. He figures 

 (fig. la, reproduced in our fig. 11) a small longitudinal flagellum 

 emerging from the apical process, but states in his text "les donnees 

 relatives a son existence elle-meme sont malheureusement insuffisants. ' ' 



During the past summer we have seen at the Marine Laboratory 

 of the Scripps Institution at La Jolla, California, in the plankton 

 taken five miles off shore a number of individuals of Erythropsis 

 and have noted its mode of progression and its orientation. The 

 animal progresses mainly in anti-clockwise circles with some rota- 

 tion about its major axis. During locomotion its prod is directed 

 posteriorly ; the ocellus anteriorly. Moreover, the transverse flagellum 

 (fig. 12) takes its origin at the flagellar pore at the point where the 

 girdle joins the sulcus anteriorly and passes in the usual direction of 

 a descending left spiral about the body in the transverse furrow. As 

 cytolysis approaches, it shortens up and may be thrown out of the 

 furrow towards the apex. It does not arise at the distal end of the 

 girdle as figured and described by Faure-Fremiet. There is, however, 

 at the distal end on the anterior margin of the girdle a notch with a 

 pit-like depression which we interpret as the attachment area. It is 

 not a flagellar pore either posterior or anterior. 



The longitudinal flagellum does not emerge at the apex although 

 the transverse one may be temporarily thrown towards that region, 

 and the area itself at times may appear to have local amoeboid move- 

 ments in the region of the tip of the sulcus which passes anteriorly 

 upon the epicone. The longitudinal flagellum is found, as figured by 

 Schiitt (1895, pi. 26, fig. 96), emerging from the posterior chamber 

 or recess surrounding the base of the prod. From this region, as also 

 from the anterior flagellar pore there passes into the cytoplasm the 

 characteristic pusule. 



