SUPPLEMENT. 
321 
Horizon. Calschiste de ToiirDai (Assise i. e); = Carboniferous 
Limestone. 
Locality. Tournai, Belgium. 
Kepresented in the Collection by three small fragments. 
Orthoceras dentatum^ Foord. 
1844. Orthoceras Gesneri, de Koninck, Descrip, des Anim. Foss, du 
terr. Carb. de la Belgique, p. 620, pi. xlvii. if. 4, a-c. 
1880. Cyrtoceras canaliculatinn, de Koninck, Faime dii Calc. Carboni- 
fere de la Belgique, p. 33, pi. xxxiii. if. 9, 9 a. 
Sp. Char. Shell long and slender, very slightly (almost imper- 
ceptibly) curved. Transverse section generally elliptical, owing to 
compression, but probably the normal form is circular, as seen in 
some specimens. The rate of increase is 1 in 10. The body-chamber 
occupies nearly one third of the total length of the shell. The septa 
are very numerous and close to each other in the young, but as the 
shell attains to maturity they become less approximate and main- 
tain a distance of about 1| line apart. The siphuncle is slender and 
nearly central in its position. The surface of the test is ornamented 
with about twenty-three very regular, prominent, longitudinal ridges, 
which are crenulated so as to form a series of very fine spinulose 
denticles throughout the whole of their length. 
Remarlcs. In changing the name of the genus it was necessary 
also to substitute another specific name for de Koninck’s, Orthoceras 
canaliculatum having already been used by J. de C. Sowerby (see 
a)ite, p. 67). 
Horizon. Calschiste do Tournai (Assise i. e) ; = Carboniferous 
Limestone. 
Locality. Tournai, Belgium. 
Fairly well represented in the Collection. 
Orthoceras subellipticum, d’Orbigny. 
1843. Orthocera ellipticum, Klipstein, Beitr. zur geol. Kenntn. der ost- 
lichen Alpen, p. 144, Taf. ix. fl*. 5, a, b. 
1849. Orthoceratites subellipticus, d’Orbign}", Prodr. de Pal^ont. Stratigr. 
vol. i. p. 179. 
1852. Orthoceras subellipticum, Giebel, Fauna der Vorwelt, Band iii. 
Abth. i. p. 237. 
1869. Orthoceras subellipticum, Laube, Fauna der Schichten von St. 
Cassian, p. 11, tab. xxxvi. fi*. 7, 7 a, 7 b. 
1882. Orthoceras subellipticum, Mojsisovics, Die Cephalopodeii der 
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