532 MOLLUSCA SUB-KINGDOM VI 
narrowed and transversely elongated, but always has an entire outline. Siphunele 
generally large, nummuloidal, and often has actiniform 
lamellae and endosiphuncles in later stages. Shells mostly 
endogastric. 
Codoceras, gen. noy, © Excessively short and rapidly 
expanding cyrtoceracones like some species of Rizoceras, 
but with large living chambers, narrow venter, and large 
siphuncle just ventrad of centre. Aperture constantly open. 
Type C. (Cyrt.) indomitum, Barr. sp. Silurian. 
Protophragmoceras, gen. nov. (Fig. 1086). Similar to 
the last, but form more compressed, and siphuncle near the 
venter (internal). Differs from Phragmoceras in having 
aperture open throughout life. Type P. (Cyrt.) Murchisona, 
Barr. sp. . Silurian. 
romphoceras, Sowb, Stout short orthoceracones and 
cyrtoceracones similar to some species of Phragmoceras, but 
Fic. 1086. straighter, stouter, and léss compressed in form, and gerontic 
Protophragmoceras Murchisont, aperture less contracted laterally. Hyponomic sinus shorter, 
a ee lly (B); boeh- and curvature exogastric. Ordovician and Silurian, 
Phragmoceras, Sowb. (Figs. 1087, 1088). Compressed 
endogastric cyrtoceracones and gyroceracones, oval in section, and venter narrowly 



Fic. 1088. 3 
, 4 
Phragmoceras Loveni, 
= ae Barr. Silurian (EB); Loch- 
Fic. 1087. kow, Bohemia. Section 
Phragmoceras Broderipi, Barr. Silurian (Btage E); Lockhow, Bohemia. showing lamellar organic j 
1/y (after Barrande). deposits (after Barrande). 
rounded. Siphuncle large and near the venter (internal), Gerontic aperture much 
contracted laterally, the hyponomie area very long and narrow. Silurian. 
2 
* 
Incertae Sedis. 
Nothoceras, Barr, Represented by the single species N. bohemicwm, Barrande, in 
which the septum turns orad, forming an inverted funnel. This funnel connects with 
che Atte Fey, 
