140 
PALEONTOLOGY OF NEW YORK. 
dental sockets. The brachidium consists of loosely coiled spirals of about four 
volutions, the cones having their apices directed toward the lateral margins of 
the valves. On the dorsal side the primary lamellae are close together, but on 
the ventral side they are wide apart, this fact indicating that the bases of the 
spirals do not lie in parallel planes but converge toward the brachial valve, so 
that the slope of the cones, which are somewhat appressed laterally, is essen¬ 
tially that of the lateral slopes of the pedicle-valve. The character of the loop 
has not been ascertained. The muscular impressions consist of four distinct 
adductor scars which are separated medially by a low, thin ridge. 
Surface of both valves covered by a few coarse plications, continuous from 
the umbones to the margins. Of these there are four or five on the lateral 
slopes. On the pedicle-valve the median pair is the strongest, and forms a sort 
of double fold with a low sinus between them. On the brachial valve there is 
a corresponding low median sinus, which contains a simple or double plication. 
The exterior is covered with fine elevated radiating lines which are usually 
interrupted to form radiating rows of elongate, lachrymiform pustules. 
Shell substance fibrous, impunctate. 
ViTULiNA now takes its place quite naturally in close association with Ccelo- 
SPiRA and Leptoc(elia. Yet the remarkable development of the cardinal area 
on both valves and the great open delthyrium are features which suggest an 
alliance with the orthoids. In so late a representative of this group of 
spiriferous genera the occurrence of these characters may probably be inter¬ 
preted as a single recurrence of an early phase of development. 
Like the genus Tropidoleptus, with which Vitulina is closely associated 
wherever it occurs, the latter appeared suddenly, attained a very prolific develop¬ 
ment, and as abruptly disappeared. In South America it appears with Tropido¬ 
leptus carinatus wherever Devonian faunas have been recognized, and perhaps 
more abundantly in the lower Devonian, in association with Leptocodia palmata, 
Salter, or L.jiabellites, Conrad, than in those faunas considered equivalent to the 
Hamilton shales of New York. Dr. 0. A. Derby, in reporting the species from 
the Province of Matto Grosso, Brazil, says; “ This generic form would seem to be 
peculiarly a South American one, since, while it is rare and only very locally dis- 
