401 



take their origin from, the regular peritoneal epithelium, especially 

 that furthest away form these »organs« i. e. near the periphery of the 

 hody, before Whe eler's ovaries begin to proliferate. The »problema- 

 tical organs« may have been the original ovaries, as Nansen surmised, 

 and they may still retain their ovarial functions , as W h e e 1 e r main- 

 tains, but they are not the sole ovaries. The body cavity is, as Whee- 

 ler points out, more extensive than formerly supposed, and its whole 

 epithelium functions as a sexual organ. 



It can be shown, and the evidence supported by figures, that the 

 dorsal portion of the peritoneum above the gut-coeca is mainly ovarial 

 in function, and various stages of the development of eggs from single 

 cells of the regular peritoneal epithelium can be demonstrated. Whee- 

 ler's ovaries, if he be right in his contentions, only come into func- 

 tion later on, and then probably proliferate their ova directly into the 

 uterus or near it, there to ripen. 



From a study of specimens of M. glahrum of various sizes Whee- 

 ler is convinced that the youngest forms are those attached to the 

 backs of the hermaphrodites, those fixed to the disc being slightly older 

 and larger than the former. 



As a matter of course we are in complete accord in holding that 

 the so-called males on the dorsal aspect of some of the hermaphrodi- 

 tes have only the male organs in a high state of development 2; but 

 Wheeler is in error in his supposition that all the youngest speci- 

 mens on the disc are larger than those seated on hermaphrodites. It 

 is quite easy to find individuals on the disc of Antedon as small and 

 smaller than the supposed males, and a comparison of the two, i. e. of 

 very small hermaphrodites from the disc and of males from the backs 

 of hermaphrodites, has furnished evidence strongly supporting my for- 

 mer conclusions. 



For the purposes of comparison a series of males were taken and 

 sectioned, and a corresponding set of what were presumably young 

 hermaphrodites from the disc Avere treated in the same way, the size 

 of the individual being estimated by the number of sections of a given 

 thickness (7i33 mm). The comparison of eight males 3, the sections of 

 which range in number from 66 to 151, with twelve small forms (pre- 

 sumably hermaphrodites) with sections form 93 to 168 in number gave 

 the following results : 



a. The males were always full of ripe spermatozoa and sperm- 



a p. 179. 



3 The eight males yielded 66, 70, 78, 79, 90, 97, 128 and 151 sections respecti- 

 vely, while the twelve hermaphrodites furnished 93 , 94 , 97, 97, 100, 112, 138, 138, 

 140, 152, 160, and 168 sections. 



