esterly: eucalanus. 37 



a body suspended in a vesicle, somewhat as an otolith rests in the 

 ear-sac. That this body is really composed of the two basal plates 

 of the apposed cells, which have stained so deeply as to be indistin- 

 guishable from each other, is shown when such a preparation is de- 

 colorized. Figure 12 (Plate 2) gives, in a semi-diagrammatic way a 

 rather typical condition that appears in sections of deeply colored 

 vom Rath material; while Figure 11 (Plate 2) is drawn from the 

 adjoining section of the same organ, after decolorization. Here 

 the line of separation between the two cells and their basal plates is 

 very plain, and from this figure may be learned the reason for the 

 peculiar appearance shown in Plate 2, Figure 24, or Plate 3, Figure 36. 

 The organs of Claus are provided with the interior bodies of Hesse 

 (phaosomes), as are the retinal cells of the median eye. The bodies 

 are similar in all respects in the two structures, and it is therefore 

 unnecessary to enter into a detailed description of their form in the 

 organs of Claus except to state that the band-hke appearance of the 

 bodies is very rarely met with. The arrangement of the bodies in the 

 organs of Claus is rather uniformly around or near the periphery of 

 the cell opposite the basal plate. This is seen best in sections (Plate 

 5, Fig. 55; Plate 3, Fig. 36), but also appears in whole preparations; 

 it is difficult, however, to show the condition in proper perspective in a 

 drawing. Figure 33 (Plate 3) will serve to give some idea of the 

 conditions as seen in an entire preparation. But any description which 

 deals with the arrangement of the interior bodies must be limited to 

 the more general features. A comparison of Figures 33 and 34 (Plate 

 3) is instructive as indicating something of the position of the interior 

 bodies in the cells. Figure 33 is a drawing of the organ of Claus 

 shown at the left in Figure 27 and viewed from the dorsal side, while 

 Figure 34 is a drawins; of the lateral face of a sagittal section of the 

 same orcjan. In both, the interior bodies are farther from the basal 

 plates than from the periphery of the cell opposite the plates, but many 

 more are seen in the section (Fig. 34) than were apparent in the whole 

 preparation (Fig. 33), if we limit our consideration to the cell (upper- 

 most in the plate) farthest from the observer in each of the figures. 

 There was really a long peripheral row of rod-like bodies ventral to 

 those actually shown in the anterior cell of Figure 33, but it so hap- 

 pened that in this particular case they were not visible at all. 



In general, then, it is a fair statement that the interior bodies of the 

 organs of Claus are peripheral; that is, near that margin of the cell 

 which is farthest from the basal plates. It can scarcely be said that 

 the interior bodies have a definite arrangement or position in regard 



