216 PALEONTOLOGY OF NEW YORK. 



Observations. Dr. Waagen has shown the necessity of adopting for these 

 shells the early term Enteletes, as Fischer's figures accompanying his diagno- 

 sis prove to be of the w^ell-known fossil Spirifer Lamarcki, although his descrip- 

 tion, suflQcient for the purposes of that time, is of little value in establishing 

 his genus. The regret expressed by Dr. Waagen at being compelled to super- 

 cede Meek and Worthen's term, Syntrielasma, will be generally felt, especially 

 as these authors had characterized their genus very accurately and illustrated 

 it with care ; they also demonstrated its close relationship to Orthis. This 

 appears externally in the bi-perforate cardinal areas, uncovered delthyria, and 

 tubulo-striate surface. It has already been suggested that these forms are 

 linked to the punctate resupinate species of Orthis (Schizophoria) through the 

 Orthis? Morganiana of Derby. Though the shells are extremely globose, and 

 their sharply plicated surface is not to be found among species of the genus 

 Orthis, they are distinctly resupinate ; the interior characterized by the great 

 development of the crural plates in the brachial valve, and the three plates in 

 the opposite valve, which are orthoid features carried to an extreme develop- 

 ment. The cardinal process is small, erect and multilobate. The muscular 

 markings have not been determined ; it is evident from analogy with Schizo- 

 phoria that in the pedicle-valve the muscular area was limited to the very 

 narrow space between the two lateral septa and was divided by the median 

 partition; in the brachial valve the wider space between the crural plates is 

 also divided by a faint median ridge. 



Before Dr. Waagen's study of the Salt-Range faunas but two species of this 

 genus were well known ; one the Enteletes Choristites or Spirifer Lamarcki, of the 

 Upper Carboniferous limestone of Mjatschkowa, Russia; the other Syntrielasma 

 hemiplicatum, Hall, sp., from a corresponding horizon in America. 



Dr. Waagen has added seven species, and proposed a subdivision of the genus 

 as follows: ventrisinuati ; ^, group of Enteletes hemiplicatus, Hall (sp.), i. e., 

 forms with a ventral sinus : dorsosinuati, forms with a ventral fold ; A, group 

 of Enteletes f err ugineus, Waagen, subequally convex shells ; £, group of Enteletes 

 pentameroides, Waagen, extremely gibbous species of pentameroid aspect. To 



