orthocekaxidj:. 
Ill 
1849. OHhoceratites Mcirtmianus, d’Orbigny, Piodr. de Paliloiit. Strati- 
graphiqiie, vol. i. p. 113. 
1851. Orthoceras Martinianum^ Giebel, Fauna der Vonvelt, Band iii. 
Abth. i. p. *236. 
1880. Orthoceras Martinianum, de Koninck, Faune dii Calc. Carbo- 
nifere de la Belgique, p. 53, pi. xliv. f. 4. 
Sp. Char. Shell straight, very slender at its inferior extremity. 
Section circular. Septa very slightly convex and rather approxi- 
mate, so that in a fragment measuring 11 inch in length there are 
22 septa. The body-chamber occupies about 1 of the total length 
of the individual ; its margin is a little oblique. The siphuncle is 
narrow and filiform, and slightly eccentric in position. The surface 
of the test is perfectly smooth, there being nothing but a few slight 
oblique undulations produced by the growth of the shell. 
Horizon. Calschiste de Tournai (Assise i. f') = Carboniferous L. 
Localities. Tournai, Vise, Belgium. 
Fairly weU represented in the Collection. 
Orthoceras Muensterianum, de Koninck. 
1843. Orthoceras irregularis, de Koninck, Precis elem. de Geologie, 
par J. J. d’Omalius, p. olG (not of Miinster). 
1844. Orthoceras Muensteriannm, de Koninck, Descrip, des Anim. 
Fossiles de Belgique, p. 506, pi. xliii. f. 5, pi. xlviii. f. 13 (excl. 
pi. xliii. f. 1, & pi. xliv. f. 1) (not of d'Orbiguy). 
1849. Melia Muensteriana, d'Orbigny, Prodr. de Pal(§ont. Stratigra- 
phique, p. 114. 
? 1873. Orthoceras Macnsterianum, Meek & Worthen, in Worthen’s 
Geol. Surv'. of Illinois, vol. v. pi. xxiii. f 5, a~d. 
1880. Orthoceras ^laemlerianum, de Koninck, Faune du Calc. Car- 
bonifere de la Belgique, p. 52, pi. xlii. f. 9. 
Sp. Char. Shell straight ; often compressed, but regularly conical 
when well preserved. Bate of tapering about 1 in o in a compressed 
specimen, measured along its greatest diameter. The septs are 
tolerably deep, and the last ones are distant about 4 lines. The 
body-chamber, of which the walls are perfectly straight, occupies 
about ^ the total length of the shell. The surface of the test is 
quite smooth. 
BemarJes. M. de Kouinck observes that the depressed form of a 
great number of specimens of this species, which is the cause of the 
elliptical form of their transverse section, is purely accidental, as is 
shown by well-preserved specimens. 
Horizon. Calschiste de Tournai (Assise i. e) = Carboniferous L. 
Locality. Tournai, Belgium. 
Fairly well represented in the Collection. 
