i8o Notes and Comments. 



(EL) and the first lateral lobe (IL), and by the ,vidth of the 

 external saddle (ES). 



(a) With narrow ES (not reaching to the outer tubercles). 

 Lipavoceras Hyatt. IL and EL about equal in depth. Genolectotype 



Ammonites striatus Bronn. 

 Becheiceras, gen. nov. IL deeper than EL. Genoholotype, Ammon- 

 ites bechei Wright (' Lias Ammonites ' pi. xli., fig. i). 

 Anisoloboceras, gen. nov. IL much deeper than EL. the ventral 

 lobules of IL almost meeting under EL. Genoholotype Am- 

 monites nautiliformis J. Buckman. 

 [h) With wide ES, reaching to the outer tubercles. 

 yEgoceras Waagen. EL and IL about equal in depth, IL symmetrical 



Genolectotype, Ammonites planicostus d'Orbigny. 

 Androgynoceras, Hyatt. IL and EL about equal in depth, IL asym- 

 metrical. Genolectotype, Ammonites hybrida d'Orbigny. 

 Oistoceras S. S. Buckman. Ribs with sharp peripheral curve. Suture 

 similar to Androgynoceras. Genoholotype, Ammonites figulinus 

 Simpson. 

 A mblycoceras Hyatt. Ribs with slight peripheral curve. IL shallower 



than EL. Genoholotype, A. capricorniis Hyatt, igoo. 

 These ammonites generally occur in the upper part of the 

 Lower Lias, where it has been usual to recognize a capricornus 

 zone overlying a striattis zone. Careful collecting has shown, 

 however, that there are several horizons with Capricorn am- 

 monites of different series and several with the involute forms 

 evolved from them. 



MR. S. S. BUCKMAN'S OPINION. 



A letter was read from Mr. S. S. Buckman, in which he states : 

 ' The family Liparoceratidae is very interesting. In its geolog- 

 ical distribution it illustrates the principle of faunal repetition 

 alluded to in my last paper communicated to the Society. In 

 its mophology, showing successive waves of capricorns devel- 

 oping into bituberculate sphserocones, which may perhaps 

 unduly hearten the protagonists of orthogenesis, it shows the 

 difficulties that confront the field-geologist until a study like 

 the author's places facts in a clear light. In its biological 

 development it illustrates the various phases of palingenesis 

 which in " Yorkshire Type Ammonites " I have called saltative, 

 cunctative, precedentive. In the last, the hastening in devel- 

 opment of one feature faster than another, we seem to have 

 the clue to the origin of species — it miakes for diversity of general 

 while tachgenesis, or the earlier acqtiirement of characters, 

 gives the differences of species. What was the cause of pre- 

 cedentive palingenesis touches the debatable ground between 

 Weismannism and Neo-Lamarckism. I confess to a predi- 

 lection for the latter — that the variations of the germ-plasm 

 were not fortuitous, but, in some v/ay, reflect modifications of 

 the somatic cells induced by their responses to differences of 

 environment. Data for solving this problem are required, 

 and evolutionary studies such as those given by the author 

 may be of great assistance.' 



Naturalist, 



