28 PALZONTOLOGY OF NEW-YORK.. 
Genus RAPHISTOMA. 
[Greek, pape, a seam or suture, and ¢roya, mouth ; from the suture or seam-like appearance in the upper 
side of the aperture.] 
Character. Shell depressed-turbinate ; discoidal spire, with three to five volutions ; suture 
close ; umbilicus moderately large; aperture subtrigonal; upper side of the volutions 
marked by a kind of seam or suture, produced by the sudden tendency backwards of the 
strie, which leaves a slight notch in the edge of the aperture. 
This genus approaches to Evompuatus in some of its characters, while it possesses others 
in common with PLEeurotomaria. The slight notch in the upper edge of the aperture, 
which is marked in the progressive growth of the shell by a simple seam or bending in the 
stria, is somewhat similar to the notch and band of PLevrotomaria ; but the outer angle 
of the volution presents no band, but a simple bending of the striz. It is probable also that 
the generic characters here given may be so extended as to include the Scalites figured 
above, as I have some evidence of the existence of the characteristic markings upon that 
shell. 
The species now described have heretofore been referred to Macturea, but the characters 
are different from the typical species of that genus.. 
48. I. RAPHISTOMA STRIATA. 
Pu. VI. Figs. 2 a, 6. 
Maclurea striatus. Emmons, Geol. Report, 1842, pag. 312,, fig. 3. 
Maclurea labiata? (A cast). Ibid. fig. 2. 
Euomphalus qualteriatus? Goxpruss, 1834; and 1844, Vol. 3, pag. 81, pl. 189, fig. 3. 
Compare Euomphalus qualteriatus. VernervuiL, Paleontology of Russia and the Ural Mountains, 1845,. 
pag. 333, pl. 23, fig. 1 a, b. 
And Euomphalus pseudo-qualteriatus. Hisincer, Lethea Suecica, 1837, pag. 36,. pl. 11, fig. 5. 
Not Pleurotomaria lenticularis. Emmowns, Geol. Report, 1842, pag. 393, fig. 2. 
Depressed, discoidal ; breadth twice as great as the height; spire nearly flat, slightly 
elevated towards the apex from the inner side of the last volution ; volutions about four or 
five, somewhat rapidly diminishing towards the apex, ventricose below; outer margin 
obtusely angular; aperture subtriangular, nearly straight above and rounded below; 
umbilicus moderately large. 
The specimen figured is somewhat imperfect ; a portion of the surface only being covered 
by strie, which are round and rather coarse. Though apparently not identical with the 
figures of Gotpruss referred to, or with the original Helicites qualteriatus of ScHLOoTHEIM 
(Nachtragen, Pl. xi. fig. 3), it is nevertheless to be regarded as a representative species ; 
and being found in the Lower Silurian strata (Strata calcarea antiquiora, Histncer) of 
Europe, it becomes interesting to inquire whether it may belong to some representative 
mass of the Chazy limestone, as our fossil is unknown in any higher position. 
