44 BULLETIN 115, UNITED STATES NATIONAL MUSEUM. 



DOLATOCRINUS ARGUTUS Miller and Gurley. 



Plate 11, figs. 4, 5. 



Dolatocrinus argutus Miller and Gurley, Bull. 8, 111. St. Mus., 1896, p. '41, pi. 

 3, figs. 4-6. 



I have listed this species separately, although perhaps only a va- 

 riant of the preceding. It has a little different aspect, being less 

 globular and wider in proportion to height than typical specimens, 

 and these characters being correlated with a shallower basal cavity, 

 lower tegmen, less angular contour, and a decidedly smoother surface. 



Horizon and locality. — Hamilton (Sellersburg) limestone: Charles- 

 town, Indiana, and vicinity. 



From 3. STELLIFEE group. 



With about 15 arms. Decanter-shaped, with broadly concave base 

 and smooth tegmen. 



DOLATOCRIUNS STELLIFER MUler and Gurley. 



Plate 11, figs. 6-8. 



Dolatocrinus stellifer Miller and Gurley, Bull. 4, 111. St. Mus., 1894, p. 20, pi. 



2, figs. 10-12. 

 Dolatocrinus hammelli Miller and Gurley, Bull. 6, 1895, p. 52, pi. 5, figs. 4-6. 

 Dolatocrinus aplatus Miller and Gurley, Bull. 8, 1896; p. 48, pi. 3, figs. 16-18; 



Bull. 9, pi. 3, figs. 13-15.— Rowley in Greene, 1903, p. 136, pi. 39, figs. &-8. 

 Dolatocrinus laguncula Miller and Gurley, Bull. 9, 1896, p. 51, pi. 3, figs. 19-21. 

 Dolatocrinus dissimilaris Miller and Gurley, Bull. 9, 1896, p. 54, pi. 3, figs. 



25-27. 

 Dolatocrinus weyZecttts Miller and Gurley, Bull. 12, 1897, p. 37, pi. 2, fige. 27-29. 



A group of synonyms representing a single well-dehned form, of a 

 thoroughly distinct facies, readily recognized from fragmentary spec- 

 imens, and differing from one another only in immaterial and incon- 

 stant details. 



Calyx decanter-shaped, with dorsal cup low, deeply and broadly 

 concave at the base, the concavity extending to the middle of the 

 first interbrachial; the tegmen rising in a high neck, which passes 

 gradually into the subcentral anal tube. Measuring to the level 

 where the tube begins to be defined, the proportionate height to 

 width is about 1:1.6 in the types of all the species. Radial ridges 

 are small and inconspicuous, and on each side of them, connecting 

 with the interbrachials, the plates are closely, deeply, and radiately 

 striated, forming geometrical figures. This sculpturing varies from 

 coarse (single) to fine (doubled) striae, without any relation to other 

 characters, the latter style being rather the most common; in the i 

 four type specimens of D. aplatus two have fine striae and two coarse. 

 A very distinct ridge connecting the centers of the radials forms a 



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