274 
NAUTILOIDEA. 
/5*p. Char. Shell straight above, but slightly curved in the lower or 
apical portion. The section is oval, the broadest extremity bearing 
the siphuncle, which is external and cylindrical. The ventro-dorsal 
diameter is to the transverse as 4 : 3, but it is sometimes reduced to 
5 : 4. The body-chamber occupies somewhat less than -l- the total 
length of the shell ; it is slightly constricted near the aperture. The 
distance between the septa amounts to about J of the ventro-dorsal 
diameter. The surface of the test is ornamented with very distinct, 
transverse, imbricating, raised lines, which become much more 
widely separated in the region of the aperture. The spacing of these 
ornaments upon the shell varies from | of a line to 1 line. 
Allied forms, such as M. Suessi, M. electum, and M. quasirectum, 
are endogastric, and may thus be easily distinguished from the 
present one. 
Horizon. Etage E (= Salopian). 
Localities. Lochkow, Kosofz, Wiskocilka, Bohemia. 
Well represented in the Collection. 
Cyrtoceras (Meloceras) clavulus, Barrande. 
1867. Cyrtoceras davulus, Barrande, Syst. Sil. de la Boheme, vol. ii. 
pt. i. p. 491, pi. clvii. ff. 1-4, pi. cxcvii. flP. 1-7, pi. ccxxiii. ff. 4, 5. 
Sp. Char. The shell is always of small size and very slightly 
arcuate, so that in a chord of 36 millim. subtending the concave side 
the highest perpendicular is 3 millim. The cross section is circular. 
The body-chamber has a length equal to the diameter of the 
aperture, and about -J- of the length of the entire shell. There is no 
sinus observable in the aperture. The septa are distant from each 
other about ^ the diameter of the shell. The siphuncle is cylindrical, 
and is situated on the convex border of the shell. The test is 
marked only with fine transverse lines of growth. 
BemaiLs. This species is distinguished by its small size. Its 
nearest ally is M. fugax, which is differentiated from the present 
species by its coarser sculpture, and by the longitudinal lines which 
ornament its apex. 
Horizon. Etage E (= Salopian). 
Locality. Butowitz, Bohemia. 
Bepresented in the Collection by two examples. 
Cyrtoceras (Meloceras) corbulatum, Barrande, sp. 
1867. Cyrtoceras corhulatum, Barrande, Syst. Sil. de la Boheme, vol. ii. 
pt. i. p. 686, pi cxxv., pi. ccxxiv. ff. 29-31. 
