nearly flat massive, composed of two series of interlocking plates, each one of which bears a pinnule. Pinnulæ long and narrow. The articular surface of the arm plates is minutely crenulated. These plates decrease in length though but little in height as they approach the tips of the arms. The surface of almost the entire animal was ornamented with granules, and the lower part with both granules and pustules. Measurements: height. breadth. length. Calyx 11 mm. 30 mm. Basals (vertical) 5½ „ 12 „ Radials 9 „ 18+ „ Brachials 7 „ 17 „ 8 mm. beyond calyx. Costals 4 „ 9 to 11 mm. Distichals 2 „ 9 „ Arm plates 2 „ 3 to 5 „ Interradial 7 „ 6 „ Aside from the markings mentioned, the calyx is also ornamented with depressions which look at first like borings of some kind, but which have the same granular character as the rest of the surface. Position and locality: Carboniferous, Upper Coal Measures, Topeka, Kan., from the Osage City shales, over the Osage coal. The type was collected by Prof. W. A. Harshbarger, in honor of whom it is named. Type now in the collection of Washburn College. In general appearance this species is strikingly like _C. craigii_ Worthen, but differs in the following respects: The body is not smooth but highly ornamented, and the anal piece is much larger. In all specimens of _C. craigii_ that I have seen the body is smooth and glossy, and shows (even when apparently unworn) no indications of former surface-markings, while this species possesses both pustules and granules, the latter covering about the entire specimen. In mature individuals the interradial is much larger. Two smaller specimens, probably younger ones of this species, are figured in the accompanying plate, showing the relative growth of the calyx and interradial. In both the ornamentation is the same as described in this species. _C. monticulatus_ Beede is from the same locality and horizon, but has long, slender arms, brachials not spinous, and the calyx is deeper. The most fundamental difference, however, is the number of arms possessed by the latter species, the number being sixteen or eighteen, while the one here described has but ten. _C. nodulifera_ Butts differs from this species in having a node at the upper part of each basal and also on the radials. It also has more acute and apparently longer spines. Mr. Butts makes no mention of finer surface-markings. The Topeka specimen is from a much higher horizon. =Aviculopecten subequivalvus=, n. sp. Plate V, figs. 3, 3_a_.