84 
PALEONTOLOGY OF NEW YORK. 
or the allied genera. Though Mr. Davidson, in all his citations of the species, 
was 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. 
1885. Neobolus, Waagen. Memoirs Geol. Surv. India: Salt-Range Fossils, pt. i, vol. iv, fas. 5, p. 756. 
Types, Neobolus Warthi, Waagen, loc. cit., p. 758, 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, 
and in the pedicle-valve is traversed by a 
broad, cross-striated pedicle-groove. The 
cardinal muscular scars lie close upon this 
groove; the central scars are faint, and in 
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 which appear to represent the external 
scars in Obolus, and the crescent in Dinobolus and its allies. In the brachial 
valve a strong longitudinally 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. 
Neobolus Warthi. 
After Waagen. 
Fig. 39. Interior of pedicle-valve. 
Fig. 4n. Interior of brachial valve. 
See remarks on page 29. 
