366 

 Baculites occidentalis, Meek. 



Plate 4, figs. 1, 1 a, h. 



Baculites ovatus (Say?), Meek (1857), Trans. Albany lust., iv, 48. 



Baculites occidentalis, Meek (1861), Proceed. Acad. Nat. Sci, Philad., xiii, 316. 



Shell attaining a medium size, very gradually tapering ; section sub- 

 trigonal, excepting near the smaller end, where it is more nearly ovate ; 

 antisiphonal or broader surface flattened so as to give its lateral margins 

 a more or less angular appearance; sides converging with slightly convex 

 outlines from these angles to the narrowly rounded or obtusely angular 

 siphonal margin; aperture subtrigonal, with the antisiphonal margin of 

 the lip nearly semicircular, and that of the siphonal side much longer and 

 somewhatcuneate-sublinguiform, while the lateral sinuosities are rounded 

 with a long, nearly straight, oblique margin on the siphonal side. Sur- 

 face ornamented with small, obscure, regular undulations, extending 

 across from the dorso-lateral angles to or beyond the middle of each 

 side, with a regular curve parallel with the margins of the lateral sinu- 

 osities of the lip. Fine rather regular but obscure lines of growth also 

 run parallel to the curves of the lip margin.* 



Septa neither crowded nor very distant. Siphonal lobe somewhat 

 shorter than the first lateral lobe, and twice as wide, provided with two 

 rather large, widely-separated terminal branches, each of which is bifid, 

 the subdivisions being armed with numerous unequal, rather sharp dig- 

 itations. First lateral sinus of about the breadth of the siphonal lobe, 

 near one-third longer than wide, and deeply divided at the extremity 

 into two nearly equal branches, each of which is tripartite, with short 

 obtuse sinuosities and digitations. First lateral lobe as long as the 

 second, but only about two-thirds as wide, and provided with three 

 principal branches on each side, the two terminal of which are a little 

 larger than the succeeding lateral divisions, and each armed with from 

 six to eight or nine small unequal branchlets and digitations. Second 

 lateral sinus a little broader than the first, but in other respects 

 very similar to it, excepting in having its corresponding branches on 

 opposite sides. Second lateral lobe nearly as wide as long, its antisiphonal 

 side being only about half as long as the other, owing to the shortness 

 of the antisiphonal sinus, provided at the extremity with four pal- 

 mately-spreading branches, the two inner of which are larger than the 

 others, rather widely separated, and each irregularly trifid and more or 

 less digitate. Antisiphonal lobe about half as long as the longer side of 

 the second lateral lobe on each side, lance-ovate in form, and provided 

 with some five or six digitations on each lateral margin, one of which 

 near the middle of each side is considerably longer than the others. 



The specimens yet known being all imperfect, it is not possible to 

 give accurate measurements from them ; though, as nearly as can be 

 determined from the taper of the longest fragments in the collection, the 

 average length of a specimen measuring 1.4.5 inches in its greater diam- 

 eter at the larger end would appear to have attained a length of 12 to 

 15 inches. 



Although I continue to regard this form as being specifically distinct 

 from the last, I am prepared to believe that more extensive collections 

 may yet show it to be only a variety of that species. So far as yet 



* On each side of the specimen represented by fig. 1 of plate 4, there is a curious 

 backward flexure of the lines of growth along an imaginary line near each dorso-lateral 

 angle as seen at (a) of the figure mentioned. As this character, however, is only seen 

 on this one specimen, it is doubtless due to some accident. 



