NO. 1 HARTMAN : GONIADIDAE, GLYCERIDAE, NEPHTYIDAE 61 



The relations of these 2 kinds of cells to their underlying struc- 

 tures, was described in detail by Oppenheimer (1902). Strangely 

 enough the distal aperture of the organs was entirely overlooked. One 

 must conclude that the technic employed for the preparation of the 

 tissues (loc. cit., p. 555) was not favorable to disclose them. Oppen- 

 heimer concluded that the organs have no muscular tissue, although 

 Ehlers (1868) had suggested such tissue because of the contractility of 

 the organs. Oppenheimer was unable to assign a function either to the 

 large basal cells, or to the cuticular external ridges. She thought (loc. 

 cit., p. 559) that the basal cells were "indifferent subcuticular cells, 

 functioning probably the same as cover cells of more complicated sen- 

 sory organs." The interesting circlet of closely spaced ganglia at the 

 distal end of the organ could also not be explained, since the distal 

 aperture was not observed. Consequently, the function of the axial 

 cells could not have been surmised. The outer cuticular ridges were 

 referred to as "wrinkling," and their function was said to be unknown. 

 Since these are actually symmetrically arranged ridges, they are pos- 

 sibly concerned with expansion and contraction of the organs. 



The structure of the proboscidial organs is clearly seen if care is 

 taken in proper orientation, especially since they are bilaterally sym- 

 metrical structures. On killed or fixed materials they are often col- 

 lapsed, or their external membranes are distorted. Since they are 3- 

 dimensional objects and very small, they are frequently seen under high 

 magnifications only as successions of optical sections. Imperfect lighting 

 and faulty optical equipment may enhance the chance for aberrant 

 views, and oblique shadows may contribute other illusions. It is only 

 after an examination of many organs in different views that their true 

 dimensional relations can be verified. To illustrate, one need only 

 point out for one species, Glycera convoluta (see below) these organs 

 have been variously shown or described as oblique plates (Fauvel, 

 1932a), incised cones (Arwidsson, 1897), or terminating in 2 points 

 (Ehlers, 1868), but never, to my knowledge, with a capelike membrane 

 that surrounds the conical organ and with a distal aperture (pi. 10, 

 figs. 5, 6). In addition, these organs have been illustrated for many 

 species of Glycera, but the distal aperture and penetrating canal have 

 not been shown. Moore (1911, p. 304) made an unusually accurate 

 observation in showing an apical pore for Glycera branchiopoda Moore, 

 and described the organs as "containing a few large sensory cells and a 

 supporting framework." Oppenheimer's studies (1902) are also note- 

 worthy in this respect. 



