155. CONTRIBUTION TO 



There are from three to four respiratory slits between the arm lobes, 

 two to four between the arm divisions and two between individual arm bases 

 of each division. 



There are twenty arms, the same as in D. ampUis, M. & G., from which 

 species the form before us, differs mainly in its greater depressed form, sharper 

 tumid character of dorsal plates and greater basal concavity. In this latter 

 feature it agrees well with D. lyoni, W. & Sp., but differs in its width, de- 

 pressed form and number of arms. 



It is not without some hesitation that we refer our specimen to D. aniplus- 



Horizon, locality and collection same as the last. 



