212 ASCOCKRAS, Ul.OSSOrKUAS. KTC. 



Genus SYCOCERAS, Pictet. 



Shell oval or bottle-shaped, straight ; septa simple; siphuncle 

 marginal. 



Silurian. Devonian. 



S. ORTHOGASTKR. Sandb. 1*1. ( .T. tig. 41)1. 



Gcnu.s ASCOCERAS, Barr. 



Shell flask-shaped; the terminal chamber not only tills the 

 front of the shell, but extends down the ventral side, nearly its 

 whole length, as :i deep cavity, which is embraced by the decur- 

 rent edges of the four or five incomplete septa ; a minute siphuncle 

 on the dorsal side. 



Sixteen species. L. and V. Silurian, Europe: Cmuidu. 

 A. BOHEMICUM. Barr. PI. 07. tig. 41)2. 



Genus GLOSSOCERAS, Man-. 



Shell like Ascoceras, but the dorsal margin of the aperture 

 ligulately extended and incurved. 



Two species. Middle and IT. Silurian. Anlicoxti, Bohemia. 



Genus APHRAGMITES, Barr. 



Shell like AttCOCerOS, but the sej)ta arc deciduous. 

 Two s]>ecies. U. Silurian. Bohemia. 



Gums PHRAGMOCERAS, Brod. 



Shell compressed on the sides, curved ; aperture contracted in 

 the middle; last chamber large; siphuncle vent nil. with radia- 

 tions ; septa simple. 



Fifteen species. Silurian to 'Devonian. Ktirupe. 

 PH. VENTRICOSI M. Stein. PI. ( .IT, tig. 4 ( ,):5. Silurian. England. 

 PH. CALUSTOMA. Barr. PL 1)S. tig. 4 ( ,4. Aperture. 



GYROCERAS, Mrvi-r. 



Shell j)lanorboid. witli separated whorls; septa simple, but 

 little curved; siphuncle suhdorsal. with radiations; last cham- 

 ber large; mouth but little contracted. 



Seventeen species. Silurian to Trinssic (?). Europe; N. 

 America. 

 G. GOLUFUSSII. PI. 1)8. tig. 41)."). Devonian. Eifel. 



