AMMONITID^. 65 



Clymenia, Minister, 1834. 

 Etym. — Clymene, a sea-nymph. 



Syn. — Eiidosiphoni-tes, Ansted, 1840 ; Planulites, Miinst., 1832. 

 Distr. — 37 sp. Devonian ; Germany, England. C imdulata, 

 Miinst. (xxxi, 11). Fichtelgebirge. 



GoNiATiTES, DeHaan, 1825. 



Etym. — Gonia, angles. Sy7i. — Aganides, Montfort, 1810. 



Distr. — About 320 sp. U. Silurian to Carboniferous ; Europe, 

 America, Australia. G. Hendowi, Sowb. (xxxii, 19). Garb, 

 limestone ; Isle of Man. 



Shell spiral, discoidal ; sutures of septa lobed ; siphuncle 

 dorsal, its tubes directed backwards ; septa concave ; margin of 

 the aperture sinuous. Aptychus a single corneous plate. The 

 genus reached its maximum development in the Devonian period. 

 The shell of Goniatites being very variable in form and the 

 species numerous, Beyrich, Sandberger and others have divided 

 them into sections, which will probably, as in the case of Ammo- 

 nites, form distinct genera hereafter. Sandberger uses the 

 characters of the sutural line for his grovips, as follows : 



1. Linguati. Lobes and saddles linguiform, rounded. 



2. Lanceolati. Lobes narrow, lanceolate; saddles rounded, 

 claviform. 



3. Genufracti. Second lateral saddle greatlj^ developed, 

 forming nearly a right-angle with the second lateral lobe ; 

 ventral lobe small. 



4. Serrati. Lobes and saddles narrow, sharp, like the teeth 

 of a saw. 



5. Grenati. Ventral lobe very small ; lateral saddle very large, 

 rounded, separated from the rounded ventral saddle by a sharp 

 lobe. 



6. Acutolaterales. Ventral lobe simple, a lobe and sharp 

 saddle on each side. 



1. Magnosellares. Lateral saddle short and wide, lateral lobe 

 rounded, ventral lobe thin. 



8. Nautilini. Ventral lobe narrow; sutural lines simply 

 arcuated on the sides. 



In some of the Goniatites the first whorls are not in contact, 

 I'ecalling the shell of Spirula. 



» 

 Arcestde. 



Shell smooth or with transverse folds, ribs or strise ; wrinkled 

 layer consisting mostl}^ of linear, interrupted strise ; impressions 

 of the mantle attachment without or with a but sligljtly con- 

 tracted opening always visible on the body-chamber. Anaptychus 

 apparently horny in Arcestes. 



