NOMENCLATURE OF STAGES OF GROWTH AND DECLINE. 



11 



It i- h!i\ iou< tli.it we cannot ao- 

 count for the nautilus-like ven« 

 tril saddle of the earlier sutures 

 of the Ammonoids, the calca- 

 shell of the protoconch, 

 . the absence of 

 tin- collar in tlic lower Goniati- 

 iinl in tin- young of the 

 higher forms, the often central 

 i of the siphon in the 

 . and many other charac- 

 aless we admit a proba- 

 ble derivation "i the Goniatitinaa 

 Brom some straight microsipho- 

 nulate form of Nautiloid It is. 

 ire, highly probable that 

 "l-liki- aspect of the 

 ime Goniatitinaa may 

 be ■ purely homoplastic charac- 

 ter, and be meaningless bo far as 

 oup is con- 

 cerned. 



7 [*he nexl or second of the 



mepioi was represented 



by a living chamber, which was 



completed by the building « »t" t In- 



upturn with it-* attached 



tig the primitive 



beginn ii<»n. This 



vied the Caecosipho- 



nula, and wi- have considered the 



i to 1"' an 



■ on «>t~ the foi mer 

 of an ancestor ha\ 

 central 

 I 1 1 1 : i \ have bad functional 



communication in •" forma by 



ii endosiphon, 



• . and in others, 

 either belonging to tin- family "i* 

 to b more primil p, they 



may have been clow 

 - The next naepionic 



ided n hen the second sep- 

 tum was Imilt in tlic modern 



f ihp pluc which the 

 aniin i ibituallj built on the • 



ol the broken or truncated end •>! n« ihell The 1 :« — t tuture 

 I, iiml the in-. 



apparent in !>••([• • howercr 



are ti i lor. When tin- outi 



of the plug « pnrl nf iu 



the 'Iran ing <>f 

 ...ill. I Ik- three diatti 



■ of the 



' .11- Itnli-li M 



Fig II, la !.. ihow 



itrongl; 

 with • 



win ii the out< 



. il the 

 \ plug* 



Ing i • Ight in 



linnor to nui. 

 .i hi 



: 



nf tin 



! . null . natural •!/•', with Si ■ 



! 



■nd ilic 



l 



» run 







