220 CARBONIFEROUS CEPHALOPODA OF IRELAND. 



FamiJii—'Pv.OLViGA^'nwjE, Eyait, 1883 (emend. Karpiuskj, 1890; Hyatt, 1900). 



[Sub-order Phyllocampijli, Hyatt, 1900 (pars), in Eastman's transl. of von Zittel's ' Cxrimdz. d. 

 Palseont.'] 



Discoidal or involiTto, compressed, suhqnadrate, or helmet-shaped in section. 

 Primitive forms ^Yith undiAnded peripheral lobe ; more specialised forms with hastate 

 lolies and saddles and divided peripheral lol)e. 



Gemis PROLECANrrES {Mnjsif<nrv\<^, 1882; emend. Hyatt, 1883, 1900).— Shell 

 discoidal, compressed, evolute, widely \iml)ilicated, with a narrow, sometimes 

 flattened periphery. Surface of test smooth or striated. Suture-line — saddles 

 entire, narrowly rounded, constricted near the base, giving them a hastate appear- 

 ance ; lobes obtusel}' pointed ; peripheral lobe undi"\aded ; two or thi'ee lateral 

 lobes ; auxiliary lobes absent or few in number ; inner (antiperipheral) lobe narrow, 

 deep, pointed, with a flat, broad, rounded lobe on each side of it. 



Devonian and Carboniferous. 



120. Prolecauites compressus. 



CONCLUDING REMARKS. 

 I. Pal.eontologt. 



In C. R. Eastman's translation of von Zittel's ' Grundziige dcr Pal^ontologie ' 

 (1900) a new scheme of classification of the Cephalopoda is introduced, the work of 

 the late Professor Hyatt, which, though partly embodying the older scheme of 

 the well-known 'Genera of Fossil Cephalopods ' (1883), contains important 

 modifications, involving the erection of many new sub-orders, groups, families, and 

 genera. The scheme is complicated and somewhat defective as it stands ; type 

 species of the new genera are often omitted, while in other cases though the 

 type species is named there is no description of the genus. An enumeration of 

 typical forms would have greatly lessened this defect. We are told, however, in a 

 note by the translator that " the classification and diagnoses are condensed from an 

 exhaustive monograph on fossil Cephalopods, at present still in MS., which 

 embodies the results of his [Hyatt's] life-study." Tlic deficiencies referred to may 



