MANUAL OF THE MOILUSCA. 
[Famity Gonratipa. Barrande.] 
Shell inyolute or straight; septa concaye in their median 
section ; sutures usually with angular lobes; septai tubes coni- 
cal, more or less prolonged, but always directed backwards. 
Siphuncle cylindrical, of small diameter, always marginal ; 
siphonal investment not persistent; conyexo-ventral margin of 
the aperture sloped, lines of growth and ornamentation of the 
shell with a corresponding sinuosity. 
The genera enumerated in this family are Goniatites, Clymenia, 
and Bactrites. Dr. Woodward includes the Goniatites and the 
Bactrites (pp. 196, 197) with the Ammonitide and the Cly- 
menia With the Nautilidze (p. 190). 
FAMILY I1J.—AMMONITIDE. 
Shell various ; septa convex in their median section; sutures 
always lobed, ramified, or denticulated ; septal tube cylindrical 
and always directed forwards. Siphuncle cylindroid of small 
diameter, always marginal; siphonal investment more or less 
- solid and persistent. Convexo-ventral ? margin of the aperture 
more or less prolonged, which determines a similar convexity 
in the lines of growth and ornamentation of the test; there are 
rare specific exceptions. 
Division I..—SUTURES LOBED OR DENTICULATED AT THE BASE. 
1. RHABDOCERAS (see p. 196). 
2. BacuinA, D’Orbigny, 1850. 
Example, B. Rouyana, D’Orb. Neocomian, France. 
Sheil like Baculites, but its lobes and saddles are not foliated, 
there being between these forms a similar distinction to that 
between Ceratites and Ammonites. 
B. acuarius, Schlotheim, is from the Oxfordian strata of 
Gammelshausen in Wurtemberg. 
3. COCHLOCERAS, Hauer, 1860. 
Etymology, cochlos, a snail-shell, and ceras. 
Type, C. Fischeri, Hauer, Fig. 8. 
Shell resembling that of Twurrilites, with the sutural Icbes 
simple, as in Lhabdoceras and Clydonites. 
10 
