284 Reviews — Messrs. Foord and Crick — Fossil Cephalopoda. 



the family Nautilinid£e containing the genera Mimoceras, Anarcestes, 

 Agoniatites, and twenty-two species ; the family Primordialidaa 

 containing a single genus, Gephyroceras, with seventeen species; the 

 family Magnosellaridse, with the genera Tornoceras, Mceneceras, 

 S]poradoceras, and twenty-six species ; the family Glyphioceratidae, 



C gj II, Hi 



_ Fig. 5. — Proviorites mjclolobus, J. PhilL, sp. a, lateral view ; I, front view (nat. 

 size) ; c, suture-line (letters to lobes and saddles as in Fig. 2 ; Ik, second lateral 

 lobe ; ho,, second lateral saddle). Carboniferous Limestone i^Grassington, Yorkshire. 

 (Fig. 125, p. 261, op. cit.) 



with the genera Brancoceras, Pericyclus, Glyphioceras, Nomismoceras, 

 Dimorplioceras, Gastrioceras, and fifty-eight species ; the family 

 Prolecanitidffi, with the genera Sandbergeroceras, Prolecanites, 

 Pronorites, Medlicottia, Agathiceras, Beloceras, and seventeen species. 



1- 



WWllRRAry 



Fig. 6. — Agathiceras Stiessii, Gemmellaro. a, lateral view, stowing spiral 

 ornamentation ; b, front view, showing somewhat constricted aperture ; c, suture- 

 line. Permo- Carboniferous, Sicily. (Fig. 130, p. 269, op. cit.) 



Group A is an interesting one, but in wealth of variation in form 

 and in richness of suture-lines and ornament, Group B must 

 necessarily far surpass it ; nevertheless, we cannot fail to observe 

 the gradual passage which takes place from the more simple forms 



