46 
NAUTILOIDEA. 
? 1872. Endoceras proteiforme, Nicholson, Geol. Mag. new series, 
vol. ix. p. 102, f. 1, 
? 1882. Orthoceras araneosum, Blake, British Foss. Ceph. pt. i. p. 124, 
pi. xvii. ff. 2, 2 «. 
Sp. Char. The shell has often a slight curvature. Section for the 
most part circular, hut in some examples it is more or less elliptical. 
The rate of increase is about 1 in 7, but including the body- chamber 
it increases to 1 in 4. The septa are about the diameter distant 
from each other. The length of the body-chamber is about times 
the diameter of its base ; it is rarely preserved owing to the tenuity 
of the test. The siphuncle is more or less eccentric, sometimes as 
much as | across the diameter, but generally very near the centre. 
The ornaments of the test are very variable, and consist of strong 
thread-like stride or riblets, very close together and forming a net- 
work ; sometimes the longitudinal, sometimes the transverse lines 
predominate. There are also transverse folds of growth (bourrelets), 
and sometimes prominent irregular longitudinal folds. 
Bemarhs. M. Barrande observes that this species is one of the 
most remarkable in the Bohemian Basin, for the number of specimens, 
the preservation of the test in a great many of them, and above all 
for the different appearances, not only of the ornaments of the surface 
but also of several other parts of the shell. This species, with its 
numerous variations of form, has never been found above Etage E. 
Horizon. Etage E, bande e ( = Salopian). 
Locality. Hinter-Kopanina, Lochkow, Bohemia. 
Yery well represented in the Collection. 
Orthoceras victima, Barrande. 
1870. Orthoceras mctima, Barrande, Syst. Sil. de la Boheme, vol. ii. 
Texte iii. 1874 (janvier), p. 286, pi. ccclx. ff. 25-35. 
Sp. Char. Shell straight. Section circular. Bate of increase 
about 1 in 7. Body-chamber relatively well developed, but the 
exact proportion between its length and the diamet-er of its base 
cannot well be ascertained, as the test covers the latter. Septa 
horizontal, regularly increasing in their distance apart, which 
amounts to about f the diameter. Siphuncle a little eccentric. The 
surface of the test is beautifully cancellated with thread-like trans- 
verse lines crossed at right angles by finer lines, so as to divide the 
whole surface into minute squares of net-like appearance. This 
sculpture can only be distinguished with a lens. 
Horizon. Etage F, bande/ 2 (=Downtonian). 
Locality. Konieprus, Bohemia.' 
Well represented in the Collection. 
