78 
PALAEONTOLOGY OF NEW YORK. 
The opposite valve shows the very peculiar feature mentioned by Mr. 
Billings, a thickened area in the umbonal region presenting the appearance of 
a false cardinal area inside the cavity of the umbo, a character which is sug¬ 
gestive of that in Lingulasma, but evidently of different function. This area 
is tripartite, bearing a deep, narrow central and two broader lateral grooves; 
about its anterior margin lie two broad scars of the same character as the 
laterals of the other valve. There are also seen the diverging furrows, which, 
starting at the marginal apex, pass over the edge of the thickened area, and 
are most deeply impressed at their anterior extremities. 
To homologize the muscular features seen in Elkania with those of Obolella 
or. any allied genus, is a difficult matter. Mr. Ford was disposed to regard the 
central depression of the pedicle-valve as an extravagant development of the 
pedicle-pit seen in 0. crassa and 0. chromatica. This appears very plausible, 
but complicates the correspondence of the other scars; and, moreover, as the 
internal scars of the opposite valves do not essentially differ in their number 
and arrangement, it would compel the assumption of a pedicle-pit in the 
brachial valve. Mr. Ford has suggested that Walcott’s species, Obolella ? am- 
bigua* from the “ Pogonip group” of Nevada, is congeneric with E. desiderata. 
Mr. Walcott’s figures, 2 a, 2 e, of the interior of the pedicle-valve, indicate the 
unquestionable correctness of \this reference. 
e/ 
Genus PATERULA, Barrande. 1879. 
PLATE IV K, FIG. 1. 
1S79. Paterula, Barrande. Systeme Silurien du Centre de la Boheme, vol. v, p. 110, pi. 95, figs, i, 
1-3; pi. 152, figs, i, 1-9. 
1884. Paterula, Davidson. General Summary to British Fossil Brachiopoda, p. 391. 
Diagnosis. “ Les deux valves, circulaires ou faiblement ovalaires, ne pre¬ 
sented qu’un bombement tres peu prononce vers l’exterieur. L’espace interne 
devait done etre tres exigu. 
“ Ces deux valves se rencontrent habituellement isolees. Cependant, nous 
figurons PI. 152, deux specimens de valves juxtaposees, qui paraissent avoir 
appartenu it un meme individu. Nous pouvons ainsi constater, qu’il n’existe 
* Palaeontology Eureka District, p. 67, pi. i, fig. 2. 
