POSTSCRIPT II. CAULOPHACUS ARCTICUS & SYMPAGELLA GRACILIS. 119 



lophodiscohexasters are considerably broader, they being of a 

 narrowly conical sliape in C. latus. The last point is considered 

 by F. E. Schulze to constitnte the chief difference between the 

 two species. I have gone into the comparison somewhat more 

 critically than F. E. Schulze did, simjily in order to contrast 

 them, as far as possible, with respect to the points utilized by 

 me for distinguishing G. Intus in the key given on p. 86 of this 

 Contribution. The diagnosis of the genus (p. 85) is in no way 

 affected by the addition of the sixth species. 



As regards Calycosoma gracUe F. E. Sch., I regret, with 

 (hie deference to the judgment of so high an authority as its 

 describer, that I can not readily accept the generic denomination 

 «iven to it. In studvinii; its characters as embodied in the de- 

 scription, one will at once be struck with the close resemblance 

 to my Sympagella anomnla in all points of the organization. In 

 fact, I can scarcely discern in it any noteworthy difference from 

 S. anomala beyond the facts that parenchymal oxyhexactins (up 

 to 1.5 mm. axial length) and oxydiactins (3-Ö mm. long and GO- 

 100 /^ broad) are much more strongly developed and that there 

 occur oxyhexasters in addition to the onychaster and the strobilo- 

 plumicome. It is possible that the two forms in question may 

 in the future be proved to be specifically identical and that the 

 differences mentioned may be found to be simply matters of 

 individuality ; but for the present they may on the ground of 

 those differences be allowed to stand as two very closely related 

 species. Be this as it may, it seems certain that they can not 

 possibly belong to different genera. Eithe]- my Sympagella anomala 

 is to be re-christened as Calycosoma anomalum, or Calycosoma 

 gracile as Sympagella gracilis ; while a further possibility is 

 that they may have to be put into a third ^enus, in which çasç 



