part 4] THE EVOLUTION OF THE LIL'AltOCERATID J- . 2->9 



to the genus Liparoceras; A. bechei and A. henleyi, which were 

 formerly placed together as species of Androgynoceras, have very 

 different sutures, that of the latter resembling the genotype of 

 JEgoceras (fig. Id), while it is necessary to establish a new genus 

 to include the A. bechei series (fig. lb). The sutures of AmbUjco- 

 ceras are likewise very characteristic, having a first lateral lobe 

 much shallower than the external lobe (fig. 1,/'). 



A. nautiliformis t which Mr. Buckman inferred from strati- 

 graphical and other evidence was the sphserocone of the JEgoceras 

 series, has a suture l which differs markedly from that of all other 

 British Liparoceratids, and resembles those of similar sphserocones 

 in the Swabian Jura (4, pi. xxix, figs. 4-6) and of certain capri- 

 corns (as, for example, A. adnethicus and A. fcrstli) also found on 

 the Continent. 2 The suture of these ammonites has an external 

 lobe much smaller than the first lateral lobe, the ventral lobules of 

 Avhich almost meet underneath the external lobe, a condition that 

 recalls certain Deroceratids (fig. 1^). 



It is extremely probable that in the Lias of the Continent occur 

 not only many species which are not represented in this country, 

 but also several genera. It is not safe to assume, therefore, 

 that the capricorns referred to A. adnethicus are the ancestors of 

 A. nautiliformis; the range of this series (from the ? valdani 

 zone to the margaritatus zone) would be unusually great. For 

 this reason A. adnethicus and A. ferstli are only referred pro- 

 visionally to the genus Anisoloboceras, which is proposed to include 

 ammonites of the A. nautiliformis tj-pe. The Continental am- 

 monites of the Liparoceratidae should be fully studied before any 

 attempt to classify them is made, since any arrangement based 

 only on a consideration of the published figures would necessarily 

 be provisional and would ultimately lead to greater confusion. 3 



(1) Series in which the Sphserocones have Unpaired 



Tubercles. 



Lipakoceeas Hyatt, 1867. 



Genolectotype : Ammonites striatum Bronn. 



Genus passing from costate serpenticone (capricorn) to bituberculate 

 sphaerocone. Whorl usually depressed, venter nearly flat or with a 

 low arch ; ornament generally coarse, the ribs passing with little or no 

 curve across the periphery. 



Body-chamber nearly one whorl. 



i I am indebted to Mr. Buckman for kindly supplying a sketch of the 

 suture of the type-specimen, which was formerly in his possession and now 

 is in the Manchester Museum. 



3 See F. von Hauer, ' Beitriige zur Kenntniss der Capricornier der GSster- 

 reichischen Alpen' Sitzungsb. K. Akad. Wissensch. Wien, vol. xiii (1854) pp. 94- 

 121, and P. Beynrs, ' Monographie des Ammonites ' 1879, pi. xxx, figs. 9 & 10. 



3 It may be mentioned here that many of the published figures of Conti- 

 nental forms are not mentioned in this paper, as they frequently do not show 

 sufficient detail to allow of even approximate correlation, while in other cases 

 the specimens are evidently quite different from anything that has been 

 found in Britain. 



