ABYLOPSIS ESCHSCHOLTZII. 227 



When Chun ('88) first described the polygastric state of this species he 

 beUeved that the Eudoxid which he observed in connection with it was identical 

 with the Aglaismoides eschscholtzii, of Huxley, but in his later work he abandoned 

 this %'iew. More recent authors, who have described Eudoxids as ^4. esch- 

 scholtzii, or as ^. quincunx, have not been able to trace the actual development 

 of the cormidia of the polygastric stage into the free Eudoxid. Fortunately 

 in several of the present specimens the stems bear groups of appendages suffi- 

 ciently far advanced for comparison with the few examples of Aglaismoides 

 eschscholtzii, as well as with the figures of the latter given by Huxley and by 

 Lens and Van Riemsdijk. As I shall show below (p. 229), there is every reason 

 to conclude that Aglaismoides eschscholtzii, is actually the Eudoxid of A. 

 quincunx; Haeckel ('88b), confused it with the Iilucioxid of ^4. tetragona. This 

 being the case, Huxley's name must be substituted for the more recent quin- 

 cunx. 



That the species recorded by Mayer ( : 00) as A . pentagona in reality belongs 

 to A. eschscholtzii, has already been pointed out by Lens and Van Riemsdijk 

 (:08, p. 25), and an examination of Mayer's figure confirms this conclusion. 

 As for Chunia capillaria Mayer, though Lens and Van Riemsdijk retain this 

 specific name, it seems to be absolutely indistinguishable from A. eschscholtzii; 

 the "long slightly curved, bristle-like spine" (Mayer, :00. p. 79) is evidently 

 nothing but the denuded stem. 



Anterior nectophore. Structurally the anterior nectophore closely resembles 

 that of A. tetragona, with which it agrees in the number and arrangement of 

 ridges and facets. It has been described and figured in great detail by Lens 

 and Van Riemsdijk. I may point out, however, that an examination of very 

 considerable numbers of each species, from both Atlantic and Pacific, shows 

 that the minor characters which they mention as distinguishing the two, e. g., 

 acute angles in eschscholtzii, blunt ones in tetragona, and the exact outline and 

 degree of curvature of the ridges, is so variable that identification from these 

 features alone is often impossible. But there is one character in the anterior 

 nectophore which appears to be diagnostic, i. e. the course of the subumbral 

 canals (c/. Plate 14, fig. 6 with fig. 1). 



Posterior nectophore. Both Chun and Lens and Van Riemsdijk, have pointed 

 out the striking differences in this structure in A . eschscholtzii and in A. tetragona. 

 Briefly stated they are as follows : — In the former the posterior nectophore is 

 much smaller, in proportion to the anterior one; and the gelatinous substance 

 much thicker. Important features are afforded by the structure of the base. 



