50 
NATJTILOIDEA. 
apparently a shell of the character he describes, so that I have ven- 
tured to place it in the same category. 
Horizon. Llandeilo. 
Locality. Near Builth, Eadnorshire. 
Eepresented in the Collection by a single example. 
Trocholites Odini, Eichwald, sp. 
1840. Clymenia Oclini, Eichwald, Scliichtensyst. v. Esthland, p. 107. 
1868. Lituites Odini, Schmidt, Archiv fiir die Natiu'kimde Liv-, Ehst- 
iind Kiirlands, p. 198. 
1860. Clymenia Odini, Eichwald, Lethaea Eossica, vol. i. Seconde 
Section de I’ancienne Periode, p. 1304, pi. li. ff. 27 a, b. 
1860. Lituites Odini, Lossen, Zeitschr. der Deiitsch. geol. Gesell. Band 
xii. p. 23. 
1881. Trocholites {Palceonautilus) Odini, Eemel4, Zeitschr. der Deutsch. 
geol. Gesell. Band xxxiii. Heft i., “ Zur Gattung Talceonautilus,'' 
p. 13. 
\_Not 1845. Lituites Odini, de Verneuil, in Murchison, de Verneuil, and 
de Keyserling’s Geol. de la Eussie d’Eiirope, vol. ii. pt. iii. p. 360, 
pi. XXV. ff. 8 a-c.'] 
Sp. Char. Shell small, discoid ; whorls depressed, slightly embra- 
cing, increasing slowly in diameter, the concave side abruptly emar- 
ginate by contact with the convex side. The siphuncle is situated 
on the concave margin. The transverse section is almost semilunate, 
i. e. considerably wider than high, the two diameters being in the 
ratio of 5| to 7. The septa are approximate, being about 1;J lines 
distant where the ventro-dorsal diameter is lines. The surface 
of the test is ornamented with fine, equal, close-set, oblique, trans- 
verse strise, which in the young shell (first whorl) are stronger than 
in the adult. These ornaments form a small backwardly directed 
sinus upon the periphery. They are distinctly visible to the naked 
eye. 
BemarTcs. The Lituites Odini of de Verneuil is certainly not the 
same species as Eichwald’s Clymenia Odini b The section in the 
former is higher than wide, in the latter it is the reverse. The 
sculpture in Eichwald’s species is also coarser than in de Verneuil’s, 
^ Eichwald himself observes, under his description of Lituites teres (Lethaea 
Eossica, loo. cit, p. 1299), that “ the Lituites teres [L. Odini] figured in the 
Paleont. de Eussie (p. 360, pi. xxv. f. 8) is not the Clymenia Odini, mihi, which | 
does not even belong to Lituites and has been confounded with the Lituites teres I 
described by me in 1840, in my rock-systems of Esthonia [Schichtensyst. von | 
Esthland, St. Petersb. p. 105]. I have here restored to it its correct name | 
'^Lituites teres].'" 
