PLATYCRINID &. 693 
crowning vice of the descriptions manufactured in this way, and one neces- 
sarily following the methods employed, is the frequent absence of any com- 
parison with other forms. All we have in many cases is the assurance of 
the author that the species is so unlike any other that a comparison 1s 
unnecessary. We have found in practice that a declaration of this kind 
is a badge of suspicion, and is one of the most common indications of a 
synonym. 
BURLINGTONENSIS GROUP. 
Dorsal cup moderately deep, cup-shaped ; plates rather heavy, and with- 
out ornamentation; arms long. 
Platycrinus burlingtonensis 0. and SHuM. 
Plate LXIX. Figs. 3a, 6, c, d, e, f, g hy 2. 
1850. Owen and SHumarp; Journ. Acad. Nat. Sci. Phila. (new series), Vol. II., Part 1, and 1852, U. 8. 
| Geol. Rep. of Wis., lowa, and Minn., p. 589, Plate 5A, Fig. 5. 
1873. Menx and Wortuen; Geol. Rep. Ilinois, Vol. V., p. 452, Plate 3, Figs. 6a, 4, c. 
1881. W.and Sp.; Revision, Part II., p. 70 (Acad. Nat. Sci. Phila., p. 244). 
Syn. P. inornatus McCursney; 1859, Description of New Species, p. 6. Figured in the Trans. 
Chicago Acad. Sci., Vol. I, Plate 4, Figs. 3a, 6, as P. burlingtonensis. 
Syn. P. exsertus Hatt, 1858; Geol. Rep. lowa, Vol. I., Part IT., p. 539. 
Syn. P. nodobrachiatus Haut, 1858 (not 1861) ; ibid., p. 542. 
Syn. P. nucleiformis Hai, 1858 ; ibid., p. 540. 
Syn. P. dautus 8. A. Mitier, 1891; Geol. Surv. Missouri, Bull. 4, p. 17, Figs. 3 and 4. 
Of medium size or less. Calyx a little higher than wide in the adult, 
width and length about equal in young specimens, the ventral disk occupy- 
ing one fourth of the height. Dorsal cup bowl-shaped, slightly spreading to 
the arm bases; the base rounded in large specimens, more or less flattened 
and proportionally shorter in smaller ones. Plates moderately thick and 
without ornamentation; the radials toward the facets somewhat thickened 
or longitudinally convex, so as to give to the cup, as seen from below, 
a slightly pentangular outline. Basi-radial and interbasal sutures a little 
grooved. 
Basal cup saucer-shaped, its height equal to half the length of the 
radials; the interbasal sutures rarely visible in the adult; the column facet 
circular and but little impressed. Radials about as long as wide, in large 
specimens somewhat longer, in smaller ones a shade shorter; wider at the 
top than at the bottom, the upper margins slightly meurving, and the 
superior angles truncated, especially at the anal side, where they form a 
——O 
