on the Genus Paleacis. 219 
remarks on the minute external and internal structure, which 
need not be repeated here. 
Locality and Horizon. Combe Hill, Henbury, near Bristol, 
in the upper beds of the Lower-Limestone Shales. Coed'y'gof 
quarry, near Wenvoe, by Cardiff, S. Wales. 
Collector. My. Spencer G. Perceval: his Cabinet. . 
Other Localities. Spergen Hill, Indiana, U.S., in the St.- 
Louis Group of the Lower Carboniferous (Milne-Edwards, 
and Meek and Worthen). 
Paleacis obtusa, Meek and Worthen. 
Sphenopoterium obtusum, Meek and Worthen, Proc. Acad. Nat. Sci. 
Philad. for October, 1860, p. 448; id. Hlinois Geol. Sury. Rep. 1866, 
ii. p. 233, pl. 17. f. 2, a-e. 
PSphenopoterium compressum, Meek and Worthen, Proc. Acad. Nat. 
Sci. Philad. for October, 1860, p. 448; id. Illinois Geol. Surv. Rep. 
1866, ii. p. 254, pl. 17. f. 1, a-c. 
Paleacis obtusa, P. cymba, et P. umbonata, Von Seebach, Nachr. k. 
Gesell. Wissensch. zu Gott. 1866, pp. 241, 242. 
Paleacis obtusa, Von Seebach, Zeitschr. deutsch. geol. Gesellsch. 1866, 
xviii. p. 308. 
Paleacis cymba, Von Seebach, Zeitschr. deutsch. geol. Gesellsch. 1866, 
p- 309, pl. 4. f. 4, a, d. 
Paleacis umbonata, Von Seebach, Zeitschr. deutsch. geol. Gesellsch. 
1866, p. 309, pl. 4. f. 3, a, b. 
Paleacis obtusa, Kunth, Zeitschr. deutsch. geol. Gesellsch. 1869, xxi. 
p. 188; De Koninck, 1872, Nouv. Rech. Anim. Foss, Terr. Carb. Bel- 
gique, le pt. p. 158. 
Spec. char. Colony “short, abruptly cuneate below, wider 
than high ; basal edge slightly sinuous in the middle; flat- 
tened sides expanding rapidly upwards from the obtuse basal 
carina. Cells from four to about nine, comparatively large, 
and of moderate depth, conical, and, where not more than four 
or five, rounded and separated by thick interstices, but be- 
coming angular, with thinner intervening partitions, where 
more crowded. Surface-strie fine, irregular, and showing a 
tendency to converge towards the middle of the base, anasto- 
mosing in such a manner as to form a kind of shagreen-like 
style of ornament.” 
Obs. This species appears to have been first indicated as a 
British one by Prof. de Koninck *; and as we have only seen 
immature and indifferent examples, or what we believe to be 
such, in Mr. Perceval’s cabinet, we have given Messrs. Meek 
and Worthen’s diagnosis in preference to drawing up one of 
our own, which, at the best, could not but have been imper- 
fect. In placing the P. cymba and P. umbonata of Von 
Seebach as synonyms of P. obtusa, we are in perfect accord 
* Nouvelles Rech. 1° pt. p. 158, 
15% 
