aaO PALEONTOLOGY OF NEW-YORK. 



The accompanying figures illustrate the interior of Ccelospira and Zygospika 



FIc. t. A. view of the spires In Oki/»pira concava flrom the ventral side.* 



Fix. 2. A view of the same (Vom the dorsal side. 



Fig. S. A Tiew of the splrea of Zyoospika from the ventral side. 



The Genus Uncites, which is characteristic of the European Devonian system, 

 has not occurred among the collections made in the State of New- York, and so 

 far as I know is not found in this country. Of the six genera of Spirifeiud.*; 

 enumerated in the preceding pages, which do not occur in Mr. Davidson's list, 

 five of them are likewise known in the Silurian formations of this countrj'. The 

 Genus Merista, which is cited as occurring in the Devonian of Europe, is not 

 known in our strata of the same age ; and it is possible that the European forms 

 of that geological period may present the same modifications as with us, and fall 

 under the Genus Meristella. Although not recognizing the Genus Retzia, wliich 

 in Europe is characteristic of the Silurian and Devonian stages, we have in Trema- 

 TOSPiKA and Riiynchospira two allied genera. The other genera of this family 

 enumerated in Mr. Davidson's list are characteristic of more modern formations 

 than those from which species are here described. 



• The disposition of the spirals in Cffii.ospiEA is not very dissimilar from the same appendages in 

 KoNiNCKiA, a Triassic genus of Brachiopoda. 



