Geological Society. 435 



Subfamily Madoqi-iy.e. 



Genus Madoqua, Ogilby. 



An example of M. kirki from British East Africa (F. C. 



Selous) agrees with the specimen of M. phillipsii described 



by me in 1910 in the structure of the pedal glands and the 



absence of inguinal glands. There were two pairs of mammae. . 



The Madoquinai (Mtvfoqua and Dorcotragus) differ from 

 the other antelopes considered in this paper by the structure 

 of the muzzle and rhinarium. 



PROCEEDINGS OF LEARNED SOCIETIES. 



GEOLOGICAL SOCIETY. 



April 17th, 1918.— Mr. G. W. Lamplugh, F.R.S., 

 President, in the Chair. 



The following communication was read : — 



'The Evolution of the Liparoceratidse.' Br Arthur Elijah 

 Trueman, M'.Sc, F.G.S. 



The Ammonites considered include several sub-parallel series, of 

 which four genera were indicated by Mr. S. S. Buekanan in 

 ' Yorkshire Type Ammonites.' The details of ontogen}^ and the 

 sutures, which had not hitherto been compared, have been em- 

 ployed in constructing tables showing both the biological and 

 the stratigraphical relations of the various species; a revision 

 of the existing classification is proposed. 



The early members of each series are similar ' Capricorn ' forms 

 with slender whorls and stout ribs (for instance, A. capricornus, 

 A. latcecosta, A. maculatus). In somewhat later examples the 

 outer whorl is swollen, and has paired tubercles (for instance, 

 A. heterogenes). From this stage the tendency is to shorten the 

 period with slender Capricorn whorls by accelerating the develop- 

 ment of bituherculation and prolonging the period of pre-costate 

 globose whorls ; thus the most advanced members of each series 

 are stout bitubereulate forms (for instance, A. striatus, A. bechei), 

 which do not pass in development through a Capricorn stage. 



The following genera may be recognized ; each includes am- 

 monites of the three types mentioned above : — 



1. An earlier group, with tubercles paired in the involute 

 stages; Radstock (Somerset) is the only British locality where 

 these ammonites have been found. 



Parinodiceras, gen. nov. Elevated whorl, paired tubercles, the inner and 



outer rows widely separated. Genoholotype, Ammonites striatus 



parinodus Quenstedt (1884, pi. xxviii, fig. 6). 

 Gen. nov. Round whorl, with the rows of tubercles placed close 



together. Genoholotype, a specimen to be figured as a new 



Bpecies, 



