. Bulletin - New York State Museum. Science. BEEKMANTOWN AND CHAZY FORMATIONS OF CHAMPLAIN BASIN 479 T . am 111 o 11 i u s ; while Hyatt at first [1884, p. 267] inclined to extend the diagnosis so far as to include all forms hitherto desig- nated in Europe as " Imperfect Lituites " with dorsal or subdorsal siphuncles. Schroder in 1891 [p. 5 fif] restricted the genus to its original Hniits and fully defined it; and Hyatt adopted [1894, p. 482] this definition which we insert here in translation as the correct one: Conch symmetrically involute. Living chamber completely con- tiguous wi
. Bulletin - New York State Museum. Science. BEEKMANTOWN AND CHAZY FORMATIONS OF CHAMPLAIN BASIN 479 T . am 111 o 11 i u s ; while Hyatt at first [1884, p. 267] inclined to extend the diagnosis so far as to include all forms hitherto desig- nated in Europe as " Imperfect Lituites " with dorsal or subdorsal siphuncles. Schroder in 1891 [p. 5 fif] restricted the genus to its original Hniits and fully defined it; and Hyatt adopted [1894, p. 482] this definition which we insert here in translation as the correct one: Conch symmetrically involute. Living chamber completely con- tiguous with preceding volutions, occupying about three fourths of a volution. Section always wider than high. Aperture expanded, with ventral sinus. Sutures simple or little lobed. Siphuncle dorsal, or subdorsal. The ontogeny which had already been investigated by Holm and the generic relations of Trocholites are fully discussed in Hyatt's above cited publication. Trocholites internestriatus Whitfield (sp.) Plate 24, figure 2 Lituites internastriatus Whitfield. Am. Mus. Nat. Hist. Bui. 1886. V. I, no. 8, p. 332, pi. 29, fig. 5-8 Discoceras internestriatum Schroder. Pal. Abhandl. von Dames mid Kayser. Bd 5, Heft 4, p. 23. Trocholites internastriatus Hyatt. Am. Phil. Soc. Proc. 1894. 32:485, pi. 4, fig. 25 This single representative of the genus Trocholites in the Beek- mantown fauna has not been observed in the beds at Valcour or anywhere else on the west shore of Lake Champlain and is thus far restricted to the outcrop at Fort Cassin. We have figured a specimen, which has been collected by Professor Perkins and which exhibits the absence of ribs on the nepionic stage and their somewhat abrupt appearance at the end of this stage better than any other specimen that we have ob- served. It also shows well the relatively large size of the umbilical perforation, a feature in which this species differs from its ^\s- 38 Trocholites i internestriatus later congeners r-^*"^ pl- 24, fig. 2, a
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