288 
NATJTTLOIDEA. 
Cyrtoceras (Meloceras) verna, Barrande, sp. 
1867. Cyrtoceras verna, Barrande, Syst. Sil. de la Bolieme, vol. ii. pt. i. 
p. 569, pi. cviii. ff. 19-22, pi. cxlvii. ff. 23-26. 
Sp. Char. The curvature in this species is considerable, and 
nearly uniform throughout the whole length of the shell. Upon a 
chord of 50 millim. in length, subtending the concave side of a 
specimen measured, the highest perpendicular was found to be 
9 millim. The transverse section is circular. The rate of increase 
measured in the septate part of the shell is about 1 iu 2. The 
body-chamber occupies nearly J of the total length of the shell. 
The distance between the septa is equal to about ^ of the diameter 
of the shell. The siphuncle is situated close to the convex border, 
but without touching the test ; its elements are cylindrical. The 
ornaments of the test consist of extremely fine transverse striae 
having a direct imbrication, and becoming more prominent towards 
the aperture. 
HemarJcs. The species most nearly resembling the present one is 
M. validum, Barr. sp. (pi. cxiv.), but it is distinguished by its more 
rapid rate of increase and larger size. 
Horizon. Etage E, bande e 2 (= Salopian). 
Localities. Butowitz, Hinter Kopanina, Bohemia. 
Bepresented in the Collection by two examples. 
Barrande observes that while the largest individuals of M. verna 
are longicones in form, those most frequently met with are 
brevicones. 
Cyrtoceras (Meloceras) arcticameratum^ Hall, sp. 
1852. Cyrtoceras arcticameratum, HaU, Pal. of New York, vol. ii. 
p. 349, pi. Ixxxiv. ff. 7 a-d. 
1882. Cyrtoceras arcticameratum^ Whitfield, Geol. of Wisconsin, pt. iii. 
Palseont. p. 360. 
Sp. Char. ‘‘Elongated, slender, gradually tapering and gently 
incurved ; septa numerous, slightly convex ; section transversely 
oval; siphuncle dorsal” [i.^e. on the external border]. {Hall.) 
Horizon. Niagara Group (Wenlock). 
Locality. Chicago, Illinois. 
Bepresented in the Collection by a single example. 
