74 PROCEEDINGS OP THE ACADEMY OF 



ishingin size from the first to the terminal one ; of these, three can be counted 

 on one side, but there may have been one or two more ; each supporting an 

 erect arm, more slender than the dorsal one, and dividing first on the third 

 piece, the inner division being smaller than the other and remaining simple, 

 while the larger one bifurcates again on the fourth piece, the subdivisions 

 being equal and of the same size as the inner branch at the first bifurcation. 

 All the axillary pieces are expanded and more protuberant at the upper end 

 than any of the others, though all of the other pieces are slightly projecting 

 at the upper end. (Ventral side unknown.) 



Column comparatively rather stout, or slightly thicker than the dorsal arm 

 below its bifurcation ; composed, two or three inches from the body, of round, 

 nearly equal, moderately thick pieces, but near the body showing a slight 

 tendency to become pentagonal, and apparently composed of more irregular, 

 somewhat roughened pieces. Surface rather distinctly granular, particularly 

 on the dorsal side of the body. 



Length of body exclusive of the basal piece, 0-48 inch ; breadth, 0-47 inch ; 

 length of dorsal arm to the first bifurcation, 0-62 inch ; entire length about 

 1-80 inch ; breadth of do., near the middle, 0*10 inch. Length of upper dorsal 

 platCj 0.15 inch ; breadth of do., 0-20 inch. 



Compared with Prof Hall's figure of the body of his C. tunicatus, and with 

 specimens we have identified with that species, this form differs in having the 

 body not narrowing upward, being as wide across, just above the constriction, 

 as at the base of the dorsal-lateral pieces ; the constriction of its sides is also 

 distinctly above, instead of at the middle ; while the outer sloping sides of 

 its dorso-lateral pieces are proportionally shorter, and directed more obliquely 

 outward. Its dorsal side, instead of being "flattened," is also distinctly con- 

 cave below the middle. Again its upper dorsal plate is proportionally smaller, 

 being considerably less, instead of more, than half the breadth of the body 

 above the middle, and only just large enough to fill the depression in which 

 it rests, without projecting al30ve ; while its lower sloping margins are rounded, 

 so as to give it a semicircular outline, instead of being straight. 



Compared with C. nodo.sus, Hall, the only other described species from this 

 horizon, it will be at once distinguished by the nodose character of the latter. 

 It likewise differs in the details of its structure from the various other species 

 described by Prof. Hall from other horizons. 



The specific name is given in honor of Prof. Frank H. Bradley, of Hanover 

 College, late of the Illinois Geological Survey, who discovered the typical 

 specimens, and numerous other fossils, at the same locality. 



Locality and Position. Crawfordsville, Indiana. Keokuk division of the 

 tx)wer Carboniferous series. 



Calceocrincs ? Wachsmuthi, M. and W. 



Body small, compressed antero-posteriorly ; above the base appproaching 

 an oblong outline, being longer than wide, a little concave in the middle of 

 the dorsal side, and with the lateral margins of the dorso-lateral pieces con- 

 stricted in the middle, and rounded and curving inward or forward, so as to 

 form a part of the ventral side. Basal piece subtrigonal, about twice as wide 

 as high, truncated its entire breadth above, for connection with the succeeding 

 piece by a widely gaping suture, evidently constructed so as to permit it to be 

 opened out on a line with the body, though in the specimens seen, it is always 

 folded close in against the ventral side ; facet for the attachment of the col- 

 umn truncating the lower end, concave and equaling about half the breadth. 

 Column comparatively rather stout, composed near the base of alternately 

 thicker and thinner pieces ; becoming more slender, and composed of longer 

 and more uniform pieces farther down ; central cavity pentagonal. Body 

 plates closely anchylosed; lower dorsal plate triangular, about one third as 

 large in the middle as the dorso-lateral pieces, which are between three and 



[April, 



