270 PROCEEDINGS OF THE ACADEMY OF [1898. 



1891. Spartina Harris & Burrows, The Eocene and Oligocene 

 Beds of the Paris Basin, pp. 100, 113 (Sept. 28, 1891). Proposed 

 as a substitute for Thaumasia Alb., 1850 (not Perty, 1830-1834). 



As Thaumasia is based partly on species of Eucalodium (Crosse 

 & Fischer, 1868), and partly on species of Urocoptis (Beck, 1837), 

 the name Spartina falls as a synonym under these groups, unless, 

 indeed, it be retained for the Paris Basin Eocene species described 

 by Deshayes as "Cylindrella" parisiensis, which is the only species 

 mentioned under Spartina by Harris and Burrows. See under Dis- 

 tcectria. 



II. ANALYTICAL KEY TO CYLINDRELLOID GENERA AND THEIR 



SUBDIVISIONS. 



(Exclusive of the generally recognized genera Lia, Macroceramus, Eucalo- 

 dium, etc.). 



I. Axis of the shell a solid, not perforated, column ; teeth of the 

 radula very peculiar, the centrals very narrow, laterals with 

 gouge-shaped cusps. 

 a. Radula with large posterior cusps (ectocones) upon all of 

 the side teeth, which are of similar form, gradually becom- 

 ing smaller from the inner to the outer edge of radula, 

 generally with no abrupt break in size between lateral and 

 marginal teeth ; rows slanting, " en chevron " (PL XVII, 

 fig. 5). Genus UROCOPTIS Beck. 



b. Axis slender and simple, without spiral lamina? or 

 other processes. Subgenus Urocoptis. 



c. Shell large, stout and fusiform ; axis straight. 



Section Urocoptis s. s. 

 c 1 . Shell small, thin and fusiform ; axis straight. 



Section Cochlodinella P. & V. 

 c 2 . Shell small, pillar-shaped ; axis sigmoid below. 



Section Spirostemma P. & V. 



b 1 . Axis with a single, strong, smooth spiral lamina, 



median in each whorl. Subgenus Arangia P. & V. 



b 2 . Axis with two series of hooks curving toward each 



other, or with a series of oblique nodes or ribs. 



Subgenus Idiostemma P. & V. 



b 3 . Axis with a single stout spiral fold crenulated at the 



edge. Section Maceo P. & V. 



6 4 . Axis with one or several spiral lamina?, the lower of 



