﻿DUMORTIERIA SPARSICOSTA. 239 



From Bum. Levesquei this species differs in having rather more gibbous whorls 

 and a smaller umbilicus. Its more distant and more irregular ribs, and the fine 

 growth-lines on the test, are also distinctions. 



It seems to me that this species is descended directly from Bum. prisca, from 

 which it differs in having fewer whorls of a more elliptical shape, and a different 

 arrangement of ribbing. Haug says, however, that " in the upper part of the 

 Jurense-zone of Swabia all the intermediate forms between the typical Bum. 

 Levesquei and Bum. Munieri are found together." 1 



The horizon of this species is, according to the above remarks, in the Jurense- 

 zone; and the little specimen came from the division Bumortieria-beds of Cam 

 Down, Gloucestershire. The larger specimen I purchased from the Wright Collec- 

 tion. Its locality is not recorded, but judging from its matrix I infer that it 

 came from Yorkshire — probably from Blue Wyke, and from the beds known as the 

 " Striatulus-shales.'* 



The species is rare, and, generally, poorly preserved. The Long and Penn 

 Woods, near Stroud, and Stinchcombe Hill, have yielded examples in addition to 

 those figured. 



PI. XXXVII, figs. 12, 13, give two views of a small specimen from Cam 

 Down, Gloucestershire, which I consider to agree with Reinecke's figure of 

 " Nautilus costiila." Figs. 14, 15, furnish two views of what is presumably a 

 larger example of the same ; and this agrees exactly with Haug's " Harpoceras 

 Mwnieri." It probably came from Blue Wyke, Yorkshire. 



Dumortieria sparsicosta, Haug. Plate XLV, figs. 17 — 20. 



1885. Habpoceeas (Dumoetieeia) costula, Haug. Beitr. Monogr. Harpoceras ; 



Neues Jahrbuch fur Mineralogie, 

 <fec, Beil.-Bd. iii, p. 664, pars 

 {teste Haug). 

 1885. Ammonites falcofila spaesicosta, Quenstedt. Amm. Schwabischen Jura, 



pi. liv, fig. 29(?). 

 1887. Dumoetieeia spaesicosta, Haug. " Polymorphic^," Neues Jahrbuch 



fur Mineral., &c, Bd. ii, p. 131, 

 pi. v, fig. 3, and woodcut, fig. 6 b. 



Discoidal, compressed, carinate. Whorls with convex sides, ornamented with 

 subdirect, irregularly distant, rather inconspicuous ribs, which disappear on the 

 outer third. Ventral area hardly defined, with a small carina. Inner margin 

 fairly defined, steep, flattish. Inclusion about two-fifths. Umbilicus deeper in 



1 Haug, ' Polymorphic!*,' p. 132. 



