\ MAI. I'll I 



times i >d it outwards 01 inwards. A simple, oorneotu 



Lol.es UMialK Mroll<_d\ incited, si | .holla I lol.e -ll< >rt e r t li:i h t he 

 lirst lateral, lobular bodie^ broadly \\ r<lur--li;i pe. 



Tin- development nf the A m:iltlie;e in 1 lie older format i< >n- has 

 already l>eeii spoken of liy WaaiMMi, and we will line only add 

 Certain observations on their structural peculiarities, which the 

 uvnu> ac.|uires in the cretaceous times. On one side \\e lind 

 forms in which the lohr> are arranged in the normal way, so 

 that after the >iphonal lobe, two lateral, and finally several 

 auxiliary lobes succeed each other ; one portion of these specie* 

 is furnished with very complicaled lobe*, whilst in others re- 

 duction occurs (A,,,. /iV////V/j./V/ ////>), which may go so far us to 

 form ceratiloid lobes (Am. J>/>i/u. Thioll., etc.)- On the other 

 hand, forms appear in the chalk which dilfer entirely from the 

 normal law of the aiTanirement of the lobes, inasmuch as live 

 lulifs may intervene betweiMi the siphoiuil lobe on one of the 

 Hanks of the 1 whorl to the sutural line. In order to understand 

 this >t met ure, one must remember that in many Jurassic 

 Amalthea- the lobular bodies are already become short and 

 broad, so that the three long, slender, terminal branches of the 

 iirst lateral have attained a certain decree of independence: 

 besides the external saddle becomes very broad, so that the 

 ;dary lobe at its l>a>e stands out strongly. Most instructive 

 of all. in regard to the transition of this arranuvment to the 

 complete independence and eijuivah-nee of all these elements and 

 the complete <\\<:\ ppea ranee of the body of the first lateral lobe. 

 is the arraiiLiement of the slitures in the form from the North 

 dermaii Neoc. >mian. which is cited as Am. (7-/ < r////V/////x. and in 

 Am. /itihhirt. Keys. 



Of these (M-etaceoiis Amaltliea- with abnormal arrMii^nnenl of 

 the lobes. tluM'e are two groups, vi/.: tlie om- has loltes much 

 toothed, and here belong Am. s///-/f///s. .Moil., ftlin't'iitn . Pek.. 

 and their allies; the other pre-eiil- a1a\i->tic reduction of the 

 h.'lies. which have here also pro^To-ed as far as the ceratitic 

 "//.<. llorm.. i'//>/-ni/,'(inu.<, d'Orb.). 



All (MH-taceoii^ A in ninni'l,-* \\\\\\ an abnormal number of l.b- 



beh. n- to A mfi///ii'i/.<. as well as the Lneater part of the civta- 



. !' which, however, a smaller portion du not 



here but i x -fiut-fiin. 



