The Relationship of the Tetracoralla to the Hexacoralla. 165 



Genus Palceacis Milne-Edwards. 



i860 Palceacis Milne-Edwards (Haime MS.). Hist. Nat Cor 



Vol. 111:171. 

 1861 Sphenopoterium Meek and Worthen. Proc. Acad. Nat. Sci. 



Phila., Vol. XII, 1860:447. 

 1866 Sphenopoterium Meek and Worthen. Geol. Surv. 111., Vol. 



11:145. 

 1866 Palceacis Seebach. Zeit. deutsch. geol. Gesell., Vol. XVIII : 



308. 

 1869 Palceacis Kunth. Ibid., Vol. XXI : 185. 

 1871 Palceacis Koninck. Memoire presentee a la classe des sci- 

 ences le 9. Mai: 154. 

 1876 Palceacis Roemer. Lethsea Geognostica, Pt. i, Lethsea 



Palseozoica, Atlas : PI. 39 and explanation. 

 1878 Palceacis Etheridge and Nicholson. Ann. Mag. Nat. Hist., 



Ser. 5, Vol. I, No. 3 : 206. 

 1892 Palceacis Miller. 17th Ann. Rep. Geol. Surv. Ind.:6i4; 



adv. sheets, 1891 : 4. 

 1896 Palceacis Hinde. Quart. Jour. Geol. Soc, London, Vol. 



LII : 440. 

 1909 Palceacis Weller. Bull. Geol. Soc. America, Vol. XX : 2y7. 

 1913 Palceacis Zittel-Eastman. Text-book of Paleontology: 106. 



Original Description of Palceacis. — The original description by 

 Milne-Edwards was taken from unpublished manuscripts of 

 Haime which were to have been included in the Histoire Naturelle 

 des Coralliaires. On account of the death of Haime, that work 

 was published by Milne-Edwards alone. The description in 

 translation is as follows : 



Polypary free but composite, rounded and very compressed 

 at its base; calices disposed, one at the summit, and the others 

 in pairs upon the lateral margins. Coenenchyma finely vesicular. 



List of Species. 



Palceacis cuneiformis Milne-Edwards. Genotype. 

 Hist. Nat. Cor., Vol. Ill, i860: 171. 

 Sphenopoterium cuneatum Meek and Worthen. Proc. Acad. 



Nat. Sci. Phila., Vol. XII, i860, 1861 : 448. 

 Locality and horizon: Spergen Hill, Indiana. Mississippian 

 (Spergen). 



