84 PALEONTOLOGY OF NEW YORK. 



or the allied genera. Though Mr. Davidson, in all his citations of the species, 

 wa.s in doubt as to its generic character, he did not manifest an inclination 

 to adopt Mr. Salter's name; but from our present knowledge it seems 

 that the term Monobolina must be accorded recognition. Externally the 

 valves are covered with strong radiating striae, as in the brachial valve of 

 schizocrania. 



Genus NEOBOLUS, Waagen. 1885. 



18S5. Neobolus, WAAnRV. Memoirs fii-ol. Sni'v. India: Salt-Range Fossils, pt. i, vol. iv, fas. .^, p. 7.'56. 



Types, Neobolus Warthi, Waagen, loc. cit., p. 75H, pi. 84, figs. 3-8. 

 N. Wynnii, Waagen, loc. cit., p. 759, pi. 85, figs. 1, 2. 



This peculiar genus from the primordial beds* of the Salt Range of India, 

 presents some important deviations from the oboloid type of structure. 



In general form and outline the shell is 

 oboloid with a somewhat transverse pos- 

 terior margin, which is slightly thickened, ['(■■■^ ^J>? 

 and in the pedicle-valve is traversed by a 

 broad, cross-striated pedicle-groove. The 

 cardinal muscular scars lie close upon this Afttr^WiToEN* 



groove ; the central scars are faint, and in l\l !:; i!!:::;::: :[ S^lti^e. 



the figure indistinctly defined, but are seen to abut against " a short thickened 

 ridge or knob " in the middle of the shell. Most striking are the broad mar- 

 ginal scars occurring on both valves, and wliich appear to represent the external 

 scars in Obolus, and the cre.scent in Dinobolus and its allies. In the brachial 

 valve a strong lougitudinally grooved callosity lies- just within the cardinal 

 margin, and this is more or less distinctly continued into a median septum. 

 The arrangement of the muscular scars other than those referred to, is not 

 fully understood. 



* See remarks on pag-e 29. 



