CLASSIFICATION OF POLYPS. 145 



IX. Classification of Polyps: (Extract condensed from 

 a Synopsis of the Polypi of the North Pacific Exploring 

 Expedition, under Captains Ringgold and Podgers, U. 8. 

 K). By A. E. Verrill. 



(Communicated February 29, 1865.) 



The report upon the collection made by Dr. William 

 Stimpson, naturalist to the expedition, having been much 

 delayed, the following tabular view of the classification 

 adopted is here presented, with the hope that, if imper- 

 fect like every other, it may, nevertheless, afford some 

 aid in illustrating the natural affinities of these humble 

 forms. 



Although in a communication read before a Zoological 

 Club at Cambridge, Jan. 1862, I attempted to demon- 

 strate the existence of the three natural orders among 

 polyps, I refrained from presenting this view in a paper 

 published last year, in order that I might make further 

 investigations upon the subject before finally publishing it. 



CLASS CNIDARIA OR POLYPI. 



ORDER I. MADREPORARIA. 



Polyps simple or compound with embryonic or rudimen- 

 tary basal orabactinal region, which has no special function 

 unless for vegetative attachment while young. Actinal 

 area well developed, form broadly expanded, having a 

 tendency in the higher groups to become narrowed 

 towards the mouth. Tentacles simple, conical. Dermal 

 tissues, and usually the radiating lamella?, depositing solid 

 coral ; the radiating plates being between the lamellae, are, 

 therefore, ambulacral and appear to originate from the 

 surfaces of the lamella? and the connective tissues extend- 

 ing across the ambulacral chambers and filling them from 

 below. Interambulacral spaces distinct. 



ESSEX INST. PROCEED. VOL. IV. S. 



