﻿MACR0CHIL1NA. 161 



his M. arculata ; and this he describes as coming nearer to M. arculata, 

 Schlotheim sp. (young state), than to any other shell he knew. This fossil per- 

 fectly agrees with the general run of our specimens, though it is much smaller than 

 some of them, and is probably a young shell. It bears just below the suture a 

 low and indistinct spiral thread. It cannot, however, be classed with the true 

 M. arculata of Schlotheim. In company with Mr. T. Roberts I compared it with 

 the figures of that shell given by Schlotheim, 1 by Goldfuss, 2 and by d'Archiac and 

 de Verneuil, 3 and also with that of M. acuta, Sow. sp., in the 'Mm. Conch.,' and 

 we then came to the conclusion that it was distinct from any of them, except one of 

 Goldfuss' s figures which seems to differ from the rest. Moreover, a fine typical 

 German specimen of M. arculata shows the same ; its body-whorl is narrower, 

 the ridges of its surface are much less defined, and it has the flat angulated 

 shoulder of that species, of which there are no signs in these Devonshire fossils. 



On the other hand, Schlotheim's figure of his other species, M. subcostata, 

 fairly represents our specimens, and there is every reason to suppose that they 

 belong to it. His figure is almost exactly like the Torquay Museum specimen 

 (PL XVI, fig. 4) when viewed from a different aspect from that figured. It 

 has its upper whorls more convex, and is a broader shell, than is usual in the 

 English fossils. D'Archiac and de Verneuil figure this species under the 

 name of M. Schlotheimi, and distinguish it from M. arculata by the absence of any 

 flat horizontal area below the suture, and by other features. Their figure appears 

 only to differ from our shells by having a shorter body-whorl and more obscure 

 ornamentation, and they assert it to be the same as Schlotheim's M subcostatus. 

 As they state the species to be very variable, and as the English fossils lie between 

 Schlotheim's form and their own, we have here a confirmation of their identity. 

 They change Schlotheim's name for reasons which are insufficient. 



Loxonema Phillipsi, F. A. Romer,* seems from his description to be identical 

 with our shell ; and Loxonema adpressum, F. A. Romer, 5 though it appears to be 

 much more elongate, is probably only a variety or contorted example of it. 



Affinities. — Clarke 6 gives a better figure of the specimen figured by F. A. Romer 7 

 as Loxonema imbricatum, which shows that its ornament consists of fine imbrica- 

 tions, and therefore that it is not, as Goldfuss supposed, identical with the present 

 species. 



1 1820, Schlotheim, ' Petrefact.,' p. 128, pi. xiii, figs. 1 a, b. 



2 1844, Goldfuss, 'Petref.,' vol. iii, p. 28, pi. clxxii, fig. 15 (exclude 15 b). 



3 1842, d'Archiac and de Verneuil, ' Geol. Trans.,' ser. 2, vol. vi, pt. 2, p. 354, pi. xxxii, fig. 1. 

 * 1843, F. A. Homer, « Harz.,' p. 30, pi. viii, fig. 9. 



5 1843, ibid., p. 30, pi. viii, fig. 10. 



6 1884, Clarke, ' Neues Jahrb. f. Min.,' Beil.-Band iii, p. 367, pi. v, figs. 19, 20. 



7 1843, F. A. E6mer, ' Harz.,' p. 30, pi. viii, fig. 11. 



