ORTHOCERAS. 147 



although the small fragment given is hardly enough for identification. He more- 

 over states the shell to be smooth, which apparently 0. multiseptatum, F. A. Romer, 

 is not. 



The shell described by Sandberger^ as 0. simplicissimum comes very close to our 

 shells. It appears only to differ from them in its rate of tapering being less (1 in 

 8, instead of 1 in 6), in the section being quite circular, and in the septa not being 

 apparently arched obliquely. One of Mr. Vicary's specimens, however, seems to 

 show that the section is circular when the shell is young, and only becomes 

 elliptic with age; and if Sandberger's figure is a front view the arching of the septa 

 would not be seen. Thus it is very possible that it may represent the same shell. 



0. multiseptatmn, F. A. Romer," as far as the fragmentary cast which he figures 

 will admit of comparison, seems chiefly to difi'er in having straight, horizontal 

 septa, and a perfectly circular section. However, under the same name he gives 

 another fossiP from the Iberger Kalk, which has deflected septa and an elliptic 

 section, so that if his two fossils belong to the same species, it would be difiicult 

 to separate it from the present form. The septa seem, however, much less 

 deflected than in Phillips's figure. 



Affinities. — 0. conoideum, Miinster,* comes so close to Phillips's species that I 

 was at one time much inclined to suppose them to be identical. It is, however, 

 a shorter shell, the rate of tapering being about 1 in 5 ; and it wants the peculiar 

 unsymmetrical contour of 0. laterale. Its septa seem rather farther apart. In 

 Miinster's plate they are between one-third and one-fourth their height apart, 

 while Foord^ states that they are two-sevenths in the specimens of that shell in 

 the British Museum. As in some of the Devonshire specimens where they are 

 shown they are only one-fifth their width apart, it would appear that the two 

 species are distinct. 



0. laterale may also be compared with 0. angustiseptatum, Giimbel,* which is the 

 same as 0. gregarlum, Miinster^ (not Sowerby). Here the septa seem about equally 

 distant ; but while those of the present species are obliquely arched there is 

 nothing in Miinster's fig-ure to show that the German fossils were so. Foord's 

 notice of this species^ leads to the supposition that the septa are close. 



0. regulare, Schlot., as given by F. A. Romer,'' appears very similar; it seems 



1 1852 ? Sandb., ' Verst. Ehein. Nassau,' p. 172, pi. xx, figs. 7 a, b. 



2 1852, F. A. Eomer, ' Beitrage,' pt. 2, p. 80, pi. xii, figs. 21 a, b. 



3 1855, ibid., pt. 3, p. 36, pi. vii, fig. 10. 



4 18'..0, Miinster, ' Beitr.,' pt. 3, p. 96, pi. xviii, figs. 4, 5. 



5 1888, Foord, ' Cat. Foss. Ceph. Brit. Mus.,' vol. i, p. 91.. 



6 1879, Giimbel, ' Geogn. Besch. Ficlitelgeb. Konig. Bayern,' pt. 3, p. 498. 



7 1840, Miinster, ' Beitr.,' pt. 3, p. 97, pi. xviii, fig. 1 b (uot la). 



8 1888, Foord, ' Cat. Foss. Ceph. Brit. Mus.,' vol. i, p. 96. 



9 1843, F. A. Eomer, ' Verst. Harz.,' p. 35, pi. x, figs. 4, 5, 8, 9. 



