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Show 364 the last in having the posterior side rather distinctly truncated, instead of being narrowly rounded. It seems to be also a proportionally shorter Shell, while the oblique depressions ( in casts) behind its beaks are deeper and more defined. Locality and position.- Same as last. GASTEROPODA. ' Genus DENTALIUM, Linnaeus. DENTALIUM Ko^ OOKSENSHS, M& k. Plate 3, * fig. 6. DentaUun Komooksense, Meek ( 1357), Trans. Albany Institute, iv, 44. Shell of medium size, slightly arcuate, and rather distinctly tapering, comparatively thin; section circular. Surface ornamented by elevated longitudinal lines or small oostse, of which about sixteen may be counted near the smaller end, where they about equal the depressions between them in breadth; farther up ( toward the larger end), there is between each two of these cost ® an intermediate smaller one developed. Pa following all these cost ® to near the middle of the shell, they are seen all to become of nearly uniform size, less distinctly defined, and proportionally more closely arranged. The lines of growth are very fine, obscure, and pass around rather obliquely. Diameter near the smaller end, 0.05 inch, and increasing to 0.10 inch in a length of 0.50 inch. ' This species is nearly related to D. gracile of Hall and Meek ( Memoirs Am. Acad. Bci. and Arts, Boston, vol. 5, p. 393), from which it may be distinguished by its thinner shell and more slender form aa well as by its less distinct lines of growth. Locality and position.- Nanaimof, Vancouver's Island; Cretaceous. CEPHALOPODA. . Genus BACULITES, Lamarck. BACULITES CHICOENSIS, Traskf Plate 4, figs. 2 and 2 a, b, c Baculites Chicoensis, Trask ( 1856), Proceed. San Francisco Acad. Nat. Sci., 85, pi. % fig. 2.- Gabb ( 1864), Report Geol. Survey California, vol. i, 80, pi. 14, fin. 27, 29, and 29 d, and pL 17, figs. 27 and 27 a. Baculites inorndtue, Meek ( 1861), Proceed. Acad. Nat. Sci. Philad., xiii, 316. Compare Baculites ovatus, Say. Shell apparently attaining nearly a medium size, straight, very gradually tapering, with a regularly ovate section, the antisiphonal aide being* little more broadly rounded than the siphonal ;* lateral sinuses of the lip * Until recently, the outer or siphonal side of the Jmmonitoid forms has been generally caUed the dorsal side, and the inner the ventral. From the position of NamtSus in its shell, however, it has been, with good reason, inferred that the outer side of the Ammonites is really the ventral side. By analogy, we may also infer that the siphonal or narrow side of the Baculites is the ventral side. I have therefore so considered it. sad, to avoid confusion, described what used to be caUed the dorsal lobe as the eiphoiAl lobe, and merelv referred to the lateral lobes and sinuses on eaoh aide ae" jSrs* and second lateral lobes and sinuses". I have also applied the same nomenclature to the Ammonites, merely counting the number of the lateral lobes and sinuses, whether many or few. |
