ORTHOCETIATID^. 
61 
specimens of Count ^Miinster's species from his locahty of Elbers- 
reuth, I can find no difference on the most careful comparison between 
them and our Silurian specimens. I find that his species has the 
section not circular, but slightly oval as in ours, aud the siphon not 
perfectly central. The species, as he notices, is easily distinguished 
from the Orthoceras annulatv.m of Sowerhy by the very much flatter 
and more approximate rings.’’ A slight discrepancy may be pointed 
out between Munster's and M‘Coy’s descriptions of 0. suhminulare ; 
the former states that the siphuncle is “ always central, never eccen- 
tric ; ” while M‘Coy describes it in his specimens as “ very slightly 
eccentric,” which is the case also with the Bohemian examples. A 
specimen figured by Portlock ^ and referred by him to the present 
species, appears to be too imperfect for identification. 
A fragment in the Collection from the “ Calcaires ampeliteux ” 
(carbonaceous limestone) of Feuguerolles (Calvados) belongs to this 
species. Several of Barrande's species of the Third Fauna have been 
recognized in these beds by MM. Tromelin and Lebesconte (loc. cit.), 
who enumerate the following in addition to 0. subannulare, viz. : — 
0. hostile, 0. lancea ?, 0. orir/innie, 0. plenrotomum, 0. severum ? 
Horizon. Wenlock Shales [England]. Etage E, bande e 2 (= Salo- 
pian) [Bohemia]. Calcaires ampeliteux ( = Third Fauna of Bar- 
rande) [France]. 
Localities. British. Dudley, "Worcestershire. — Foreign. Hinter 
Kopanina, Dlauha Hora, Lochkow, Bohemia ; Feuguerolles (Cal- 
vados), France. 
Well represented in the Collection. 
Orthoceras dulce, Barrande. 
1868. Orthoceras dulce, Barrande, Syst. Sil. de la Bolieme, vol. ii. 
Texte iii. 1874 (Janvier), p. 321, pi. ccxciv. ff. 4-8 and 10-14, 
pi. ccxcv. ff. 1-3, G-2o, 27, and 29, pi. cccclxxxviii. case v. ff. 1-3. 
1877. Orthoceras dulce, Barrande, ibid. Suppl. et S^r. tardive, p. 207, 
pi. dxi. ff. 11-14. 
Sp. Char. Shell invariably curved in some part of its length. 
Section always circular. Bate of increase verj- slow, about 1 in 16, 
but reduced to almost zero in the body-chamber. The extent of the 
latter is not exactly known, owing to the extreme fragility of the 
shell. The septa are distant about | the diameter. The siphuncle 
is central. The surface is ornamented with very prominent annula- 
tions, the spaces separating them being about equal to the latter. 
The annulations are generally a little oblique. Furthermore, the 
whole of the surface of the test is covered with transverse strije, very 
1 Keport on the Geol. of Londonderry, &c. by J. E. Portlock, 1843, p. 368, 
pi. XXV. f. 8. 
