56 BULLETIlSr 115, UNITED STATES NATIONAL MUSEUM. 



15 to 18 arms; three^have less than 15; one only 10; and the remain- 

 der have more, up to 20 and one abnormal 22; so this may be con- 

 sidered as typically a 15-armed form, as distinguished from the 

 approximately 20 arms of corporosus. The generally higher and 

 narrower calyx as compared with that of the corporosus type, and 

 the more ventricose tegmen, with smoother plates rather obscurely 

 defined and tending to develop small spinous nodes, are the charac- 

 ters to be noted. None of the Miller and Gurley types are good 

 representatives of the mature stage of this fonii, and I have given a 

 figure of the type of Wachsmuth and Springer's D. eicosidactylus 

 which is much more characteristic; it attains even a larger size than 

 this. I also figure a 10-armed specimen which belongs either here 

 or under D. hellulus, as one chooses (pi. 16, fig. 5). Minimum stages 

 of both species are shown by plate 16, figures 7, 8. 



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

 town, Indiana, and vicinity. 



DOLATOCRINUS BELLULUS MUler and Gnrley. 



Plate 15, figs. 1-6; plate 16, figs. 4-7 (?9). 



Dolatocrinus bellulus Miller and Gtjrley, Bull. 6, 1895, p. 57, pi. 5, figs. 16-18. 

 Dolatoerimis basilicus Miller and Gurley, Bull. 9, 1896, p. 4.3, pi. 3, figs. 1-3. 

 Dolatocrinus noduliferus Rowley in Greene, 1903, p. 140, pi. 41, figs. 1-3. 



This and the next form are distinguished from those preceding by 

 reason of having prominent nodes and discontinuous median ridges 

 along the radial series, while they differ from each other mainly by 

 the ventricose, lobed tegmen with small spinous tubercles in this 

 species, as opposed to the low, non-spiniferous tegmen of the next 

 following. 



Hoiizon and locality. — Hamilton (SeUersburg) limestone: Charles- 

 town, Indiana, and vicinity. 



DOLATOCRINUS NODOSUS MUler and Gurley. 



Plate 15, figs. 9-11. 



Dolatocrinus nodosus Miller and Gurley, Bull. 7, 111, St. Mus., 1895, p. 56, pi. 



3, figs. 1-3.— Rowley in Greene, 1903, p. 163, pi. 48, figs. 1-3. 

 Dolatocrinus tuberculatus Wachsmuth and Springer, N. A. Grin. Cam., 1897, 



p. 324, pi. 25, fig. 3. 

 Dolatoerimis multinodosus Rowley in Greene, 1903, p. 147, pi. 44, figs. 1-3. 

 Dolatocrinus elegantulus Rowley in Greene, 1903, p. 150, pi. 44, figs. 10-12. 



Like the last, except for the flat tegmen, without nodes or spines, 

 but sometimes with very small pustules, which may occur on any 

 tegmen classed as smooth. 



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

 town, Indiana, and vicinity. 



